First of all, let's assume that the chips are indeed "play till you lose," meaning you get paid on a win but the chips remain. If they're "one play win or lose," they're only worth half as much.
So for the table game option, the best games in terms of EV, in descending order, would be: actual blackjack (3:2), craps (pass line), shitjack (6:5), or a carny game.
If you play VP at a Caesars property, you'll be hard-pressed to find anything over 98%, even at high denoms. If you did find 8/5 Bonus (you'll never find 9/6 JOB), that would be better than craps but worse than BJ.
You refer to "strategy," and to me, the best strategy for free play is to try to convert it to actual money. The ACTUAL optimal strategy is to play it on the highest EV game available. These approaches can be contradictory. I tend to play the least volatile game, even if it's not the absolute best in terms of EV, because I just hate the idea of turning, say, $100 in free play into $15.
Therefore, if you just want to burn through it...take the free play and run it through a $5 denom game. You'll get 40 hands. Your results will be along a pretty wide bell curve. If you want the best value: BJ or craps (again, not shitjack). If you want the most play in terms of duration/amusement, craps is the way to uh, roll.
The psychological trap to avoid is treating the free play as some kind of "take a shot." That free play is part of your bankroll. Don't think of it any differently than you do about the money in your wallet.
