Having played a few tourneys on Fulltilt that might be somewhat similiar in nature (ie. the CanadaCup freeroll, although I'm guessing it has marginally better skill level of play than the reg. freerolls.... at least as far as I noticed from running some player stats.). What I've noticed is that even very deep into these tournies you will get ALOT of noobs who are limping in on very high blinds, "WANTING TO SEE THE FLOP!!!!"... generally weak poker imo. Try to differentiate between the ones who are actually limping in on big hands but are afraid to committ any chips preflop (ie. like AQo, AJ in late pos., med. pp's, etc.) and the others who are limping in on weaker holdings. Instead of joining in with them, look for spots to re-steal (as I'm sure it is difficult to find spots to steal blinds when there's so often 2, 3 or more players still limping in). Pick a decent spot and either re-raise large OR if in late position or on blinds and guy in CO or on BTN is continually limping in weak... just raise huge or shove it allin and put them to a decision (esp. if stack size is in the 15-22 bb size... good size for resteals... too shallow to call raises and see flops in most cases).
Optimally you want to look for spots where you can steal the blinds, perferably in Late position... but as mentioned, sometimes you aren't going to find these spots. Look for spots to re-steal!! Another scenario that I see happen frequently - - you get a player to your right who is regularly min-raising into your blinds or blinds just to the left of you. Shove it ALLIN on this guy (most cases he doesn't want to risk a big pot, but just wants to keep stealing for minimal investment).
If you're in BB & larger stack in SB keeps limping in (Comp SB) and then auto-bets flop.... reraise ALLIN preflop, sometimes with any two cards. This should shut him down.
Late stage tourney play.... "you must be willing to die in order to live"