Atlantis: out-of-town visitors can electively convert comps to free-play during any stay. Just ask at booth. There might be some push-back but a manager or "team leader" can authorize transaction. This is a reasonable approach because "conversion" days are random and visitors often need to plan trip well in advance of monthly calendar.
Silver Legacy: the quarter FPDW uprights award the same free-play and comp percentages of other VP games (my experience). I've heard other players have had benefits reduced for exclusive play here, so I would not recommend over-doing it. Gas cards on Fridays: 250 points ($5K coin) gets a $25 card (.5%). Similar deal for Visa gift cards on Sundays. A warning: SL runs a daily average operation for marketing and card tier, so avoid using your card on short-play days.
Peppermill: there's a free slot tournament, usually on Thursdays, 12-8, that's worth a shot. You get one entry with a card swipe and you can earn additional entries up to max. of 11 at the rate of one entry for every 10 points. In addition to cash and free play for top 10 finishers, each entry will also get you $5 in free-play. It's a nice way to pick up additional free-play, especially if you can find a machine that awards a point for <$40 :-). You probably need an individual score of over 8K to get in the money.
Had a strange hand: held two pair on a 10 line game. Hit 5 full houses on the draw. This caught my attention so I took a closer look. Turns out I drew the same card (ten of spades) to complete all five full houses. You play long enough on random machines and you will see some weird stuff! Too bad I wasn't holding a 4 card royal in spades 