The pot is big, so I like it. Reads would help a lot. Betting into the PFRer signifies a certain amount of strength.

When it's checked to you on the turn, I'm inclined to think UTG more likely has a draw. In this case, you are getting better than 4:1 on bluffing both streets; which I'm inclined to think is worth it.

I'll wait for other's view on this one.