I'm hoping someone with a lot of knowledge of Latin will respond.

I'd also like to add:  Do you guys think Rosetta Stone would be a good way to learn Latin?

Start here:

http://www.gettingstartedwithlatin.com/

A link to a book does not answer my question.

Pronunciation, declensions and cases, and vocabulary.  Are these all that one will have to learn?

Yes/no.

If no then what else?

You should have to worry too much about pronunciation.

Grammar and vocabulary seem to be the most important things.

It will help a lot to have reading material. See the books in the Loeb Classical Library series.

Memorization really is the key.

I took Latin for 7 years, including high school and college, so I know what I' talking about.

Memorize the five declension so that you can literally rattle them off in your sleep. That's just nouns.

Then, memorize the conjugations. 4 conjugations, with different forms active and passive, indicative and subjunctive, for present, imperfect, future, perfect, pluperfect, future perfect.

OK, that's a little extreme. I would start of by just learning the first three declensions, since they are the most common, and the following conjugations:

Active Indicative, present, imperfect, future, perfect, pluperfect, future perfect.

Once you have that down, you'll be able to read short and simple Latin stories and phrases, and a decent amount of the Common parts of the Mass. You should also be able to at least get the gist of the four Gospels in the Vulgate.

I would also try reading some Classical authors. Naso is the easiest, IMO.

For Latin books....I recommend Henle, just because that is what I'm most familiar with.

I doubt that an "immersion" program would be good for Latin, simply because grammar and syntax is a lot more complex than most modern languages. It is however more logical, so that's a plus.

The most important thing, after memorization, is to get a feel for the sentence structure; it is very different than English.

English: Subject-Verb-Object. For example: Rome is in Italy.

Latin: Subject-Objecct-Verb. E.G.: Roma in Italia est.

There is a lot more to this subject.....I may add more if time allows.

Is this all?

Pronunciation
The five declensions and their cases
Vocabulary

Is there something missing?

This is just scratching the surface.  You did not mention verbs.  You need to understand the subjunctive mood.  This involves learning the forms for the various tenses and learning how to use them.  While subjunctive is not much used in English, it is important in Latin, especially Ecclesiastical Latin.  

[quotePronunciation
The five declensions and their cases
Verbs
Subjunctives
Vocabulary [/quote]

Sentence and paragraph construction......Subjunctives are simply a subtype of the conjugations.