Reddit reviews Latin Demystified: A Self Teaching Guide

I can't address Greek, but I've got Latin down. (I spent a couple years learning Latin and haven't forgotten all of it).

/r/latin could easily direct you to some sources.

http://en.wikibooks.org/wiki/Latin is a good(ish) reference grammar.

I learned all my Latin in a classroom setting via Cambridge Latin Course, which is pretty good, but maybe not the best without a teacher. I've taken a look at Latin Demystified, but I just used it as a refresher. For dictionaries, I have a copy of Cassell's Latin Dictionary, but I use Wiktionary a lot. After you get all of the grammar down (I'd recommend Latin Demystified and then some other self learners till you're really comfortable with everything), I'd try and go through the A Legamus series of books. The first few translations probably won't be A+ material, but if you keep practicing, you'll get it down I'd think.

Definitely learn Latin! It will make your life wonderful. If you're going to start, I would suggest Wheelock's Latin or a solid self-teaching book Latin Demystified; it might not seem very good but I've used it and I promise that it makes studying on your own very easy!