The flop call isn't that out of the question, because as long as SB and BB just call you are almost getting immediate odds for your set. I would probably still fold because there aren't many hands that are 3 betting you preflop that don't have you beat here. Not only that, but the SB or BB might check raise which would commit you for another bet. On the turn I would just check and fold to a river bet. I think that despite the fact that he checked, UTG has ome kind of a weak ace, and if you bet the turn I believe you are getting called down by a better hand. Betting here and taking a free showdown wouldn't be a bad line if you think some of these players are able to lay down a better hand than you have.