Ugh.. this would be so much easier with bigger stacks at 100NL.
I guess you gotta call this for the following reasons:

1. PFR - you beat most standard raising hands and smaller flopped sets
2. flop/turn betting rounds - villain looks like he has a made hand rather than a draw and your betting hasn't indicated great strength
3. pot odds - you are getting 2:1

Reasons not to call:

1. This is 25NL and he could be playing any cards in any way

At some point you have to pay off the donks. I do it all too often.