If you want to win a big 3000+ public freeroll, you need to get chips quick. I'd rather double or triple up early or go out, I don't want to fight my way through the masses for 4 hours only to get sucked out by some big stack calling station. Here's my advice:
-shove any marginal or better hand asap. Seriously. Any Ace, K10+, 66+, suited connectors over 45.
I know this isn't really "playing poker," but until you get at least halfway through one of these things you're not really playing poker anyway, and to think so would be bad. Just shove, if you get busted, no big deal, and you haven't wasted a bunch of time. If you do 2x or 3x your stack, then you can sit back, mellow out and start to play some cards.
I'm probably going to get flamed for suggesting this, but whatever - I've taken down that
bodog freeroll that you mentioned, and gone deep in a few others using this strategy.