I saw these quite some time ago, but just started to skim through parts again and had forgotten a lot of this.  Lots of very interesting detail about Vatican II.  Below I pulled some of the ones that caught my attention.

https://novusordowatch.org/2014/08/diaries-mgr-joseph-clifford-fenton/

Our Maltese friend (who was born in Alexandria) told us that he saw Spelly [Cardinal Francis Spellman] coming out of the [1958] conclave looking white and shaken. (Nov. 2, 1960)

I had always thought that this council was dangerous. It was started for no sufficient reason. There was too much talk about what it was supposed to accomplish. Now I am afraid that real trouble is on the way. (Oct. 13, 1962)

I started to read the material on the Liturgy, and I was shocked at the bad theology. They actually have been stupid enough [to say] that the Church is ‘simul humanam et divininam, visibilem et invisibilem’ [at the same time human and divine, visible and invisible]. And they speak of the Church working ‘quousque unum ovile fiat et unus pastor’ [until there be one fold and one shepherd], as if that condition were not already achieved. (Oct. 19, 1962)

I do not think that any little work on our part is going to bring good to the Church. We should, I believe, face the facts. Since the death of [Pope] St. Pius X the Church has been directed by weak and liberal popes, who have flooded the hierarchy with unworthy and stupid men. This present conciliar set-up makes this all the more apparent. [Fr.] Ed Hanahoe, the only intelligent and faithful member of [Cardinal] Bea’s secretariat has been left off the list of the periti. Such idiots as [Mgr. John S.] Quinn and the sneak [Fr. Frederick] McManus have been put on. [Fr. George] Tavard is there as an American, God help us. From surface appearance it would seem that the Lord Christ is abandoning His Church. The thoughts of many are being revealed. As one priest used to say, to excuse his own liberalism, which, in the bottom of his heart he knew was wrong, ‘for the last few decades the tendency in Rome has been to favor the liberals.’ That is the policy now. We can only do what we can to avert an ever more complete disloyalty to Christ. (Oct. 19, 1962)

I never thought that the episcopate was so liberal. This is going to mark the end of the Catholic religion as we have known it. There will be vernacular Masses, and, worse still, there will be some wretched theology in the constitutions. (Oct. 31, 1962)

They plan to leave off this television nonsense in a day or two, and then take up the Church Unity then. That will be a disaster. If I did not believe God, I would be convinced that the Catholic Church was about to end. (Nov. 23, 1962)

…some other people believe what I have thought for several months, namely, that John XXIII is definitely a lefty. This nonsense to the effect that he is ‘deceived’ or ‘mal servite’ is disgraceful. He is the boss. (Nov. 25, 1962)

The articles in the Milan Corriere della Sera tell of the Pope’s connection with [the excommunicated Modernist priest Fr. Ernesto] Buonaiuti, and they make him look like a real Modernist, at heart. He probably is. (Nov. 26, 1962)

I am afraid that they are going to foist a lot of nonsense on the poor Catholic people. (Mar. 6, 1963)

Liberal Catholicism as understood by these men was and is the system of thought by which the teaching of the Catholic Church were represented as compatible with the maxim that guided the French Revolution. (May 11, 1963)

[Fr.] Ed Hanahoe gave me two books on Modernism. In one of them I found evidence that the teaching in the first chapter of the new schema on the Church [the one that became the Vatican II dogmatic constitution Lumen Gentium] and the language are those of [the excommunicated Modernist Fr. George] Tyrrell. May God preserve His Church from that chapter. If it passes, it will be a great evil. I must pray and act.” (Sept. 24, 1963)

M [Fr. John Courtney Murray] has just come in to see the triumph of his false doctrine [of religious liberty]. (Sept. 21, 1964)

[Cardinal] Lienart is speaking. He is insisting that all Christians have the Jews as a common source. He ignores the fact that the religion of Israel and Juda before the public life [of Christ] was one thing, and past. Christian Judaism is quite another. The center of Jєωιѕн religion after Christ is and has been the denial of Christ. (Sept. 28, 1964)

The more I hear of the speeches and of the progressiveness, the more I am aware of the fact that this council is one of the most important events in all the history of the Church. (Oct. 9, 1964)

[Mgr.] Joseph Quinn just told me that the H.O. [Holy Office] is being abolished and that Card. Ottaviani will not be the head of the new, non-supreme, congregation which will take its place. The old man is being humiliated. He is a saint. (Nov. 21, 1964)

The part on ecuмenism [in the text of the commission] is a joke. It reads like a 19th century text, or a second-rate article in a leftist magazine. (Oct. 28, 1965)

The day before yesterday I had dinner with O [Cardinal Ottaviani]. On the way back I found that the Pope had written to O about [schema no.] 13. I saw the letter. It was a great mistake to let that one, the one on religious liberty [which became Dignitatis Humanae], and the one on non-Christian religions [which became Nostra Aetate] get by the council. (Nov. 26, 1965)

This afternoon John McCarthy called. He is a believer, and he has some confidence in Montini [Paul VI]. He told me that O[ttaviani] has written some articles entirely revising his old position. It must have been under pressure from Montini. (Sept. 24, 1966)

He did qualify some of his remarks with things like -- If I didn't believe in God, I'd say the Church is finished."

In terms of characterizing the damage (he expected to be) done by the Council, I think it's written from the human perspective.  He's there and sees this "stupid" (his words) Liberal theologians running around writing Council docuмents, so it's very tempting for him to see the docuмents there as the garbage that they were.  He would need to take a step back and consider it from a supernatural perspective and what that means.

In the end, however, he did succuмb to a more theological perspective.  He himself wrote a long article about infallible safety, where he stated that it's not possible for some teaching presented as normative for the entire Church to be radically defective or harmful to souls.  As a result, he ended up constrained to believe this, forcing him despite his observations made from a natural perspective to apply a hermeneutic of continuity to the end result of V2:

I have just about made up my mind to start a new book. I shall write on the notion of the Church. Nothing like this has appeared since the Council. Within the book I hope to have quite a bit to say about the Council. I must be very careful. If a sincere Catholic writes a book it’s either ignored or brutally attacked. I must make no mistakes. My main thesis will have to be that the Catholic theology on the Church has been improved but in no way changed by the Council. I must start with the basic notion of the Church, which is that of a people ‘transferred’ from the kingdom of darkness into the realm of light. The Council left out the background of the Church. It minimized or glossed over the fact that the Church faces opposition, not just from hostile individuals, but from the ‘world.’ (Nov. 23, 1968)

Lad, when we were at Catholic U., Msgr. Bob Trisco told us Church history doctoral students about Msgr. Fenton's evening habit during the Council of eating raw garlic and then heading out to those trattoria where the liberal bishops and periti would dine and chat. Fenton would get up real close to talk to these modernists, choking them with the garlic odor on his breath.

Interesting. I wonder what he would have to say now, after 60 years of Vatican 2?

I wish we had more resources like this, more first-hand accounts of Vatican 2 from people who were on the inside. I bet it would be fascinating. If Cardinal Ottaviani, for example, wrote a diary and someone could get their hands on it and publish it, I would sure love to see it!

Having a round table with +Thuc, +ABL Cdl. Ottaviani and Msgr. Fenton would be pretty much the defining meeting on The Crisis. Only if.

I imagine +Thuc and +ABL would feel entirely justified and probably would have consecrated more if they had lived another 10 years. +Thuc never lived to see Assisi.