[imported_The Vibesman]

I must admit, I play these types of hands horribly.

With UTG+1 calling the whole way, there are a few possibilities as to what he had. Suited ace with a weak kicker (if he would limp in EP with that), low made pair and gutshot draw (again, if he would limp with low suited connectors) or a small pocket pair (seems the most likely limping hand in that position). The only thing you are beating at showdown is a completely busted str8 draw, I think, and I can't see many players limping early position with a two-gapper (of course, i do see that on micros a lot, but I am assuming people play a tiny bit tighter at 1/2 than at .50/1). So I can't see any way checking will win you the pot. There is a possibility that opponent has 6-7, and he will definitely fold that if you bet, but he also may very well fold some hands here that could beat you. There are 6 BBs in the pot, I think (at this point in the hand) it is worth throwing another bet at it in hopes of getting him to fold a better hand. I think it's the only chance to win. Checking could also cost you the pot, in the off chance that you check and he bets that busted gutshot 6-7 and you fold. I realize that it is unlikely that he has that, I am thinking small pair of some sort.

Long and short, I think the river bet is the only realistic chance to win. Pot's big enough for me to give it a shot, fold to a raise.

edit, after reading other responses: I had not addressed anything but the river, but I would fire at this flop after raising pre-flop, with only two limpers. Of course, I fire at a lot of flops after raising pre-flop, esp if it comes up w/ an ace, as anyone without one will almost immediately give credit to the pre-flop raiser for having one. I would also fire at the turn, as many will call the small flop bet on the draw but will fold the large turn bet. It is only after the turn call that I put opponent on a pair.
I hadn't really considered a check-raise; opponent may check thru w/ a small pair and have us beaten, opponent may call the checkraise due to the fact that the pot will now be about 10 bb's before rake and he has already invested one bet on the river. Plus we are risking 2 BB's at this point to win the 6 in the pot at start of river action, which seems to make it a worse investment. I'm interested in arguments to the contrary, however.