If I can reco anything:
1. Get your faucets (perlick, or anything forward sealing) now. Yeah, its money you might not have, but find it, you'll love pulling the tap for a pint, and so will anyone who uses it. You probably won't heed this advice, but you should, and get as many as you think you might need now. I bought 3, have room for 5, and should have bought 5.
3. Buy, procure, whatever, as many kegs of your decided type as possible. Used ball locks are getting tougher to find at decent prices. I've watched prices on these climb inside of the 3 weeks I was planning/building mine.
2. Collar on freezer body build is MUCH simpler and easier to do, but some people (bunch of skirts if you ask me) complain (whine) about lifting a full size keg over the collar.......
Its really not a big deal in practice, but for me, collar on body was much easier to build and I don't worry about the added stress on the hinges or buying a separate set of hinges. You also don't have to worry about sealing 2 separate surfaces, probably not hard either way, the choice is yours.
Half of my post should be taken lightly, especially those with reasons that don't allow them to lift a full keg over a collar, but the picnic tap thing makes me cringe. I know people's financial situations are all different, but if you are going to dedicate a freezer to something other than beef and some fish you caught, you have to go for it, spend the money now. My .02