This hand is really poorly played up to the river.

On the river I'm folding, there is just no hand he can have you beat and no way he's drawing.

"bet 30 is called"

Who bet it - you or your opps?

Betting is confusing - 30 is an overbet and so is the 100 which indicates the bettor(s) is/are looking to end the hand sooner than later at showdown. Having been caught bluffing at a pot just recently, indicates this guy is capable of doing it again and an overbet would be consistant with that.

You have Top and bottom pair so he'll need a king with a better kicker (but he limped/called preflop so how good could it be compared to yours? Would he limp/call AK, KQ or KJ?) or trips of which there are 2 possibles 5s and 7s (3 if the guy is a moron and limped Ks). A limp/call preflop often enough indicates a small - mid pocket pair but a lot of loose players love to play A-little suit so A-5s is a defenate possibliity.
However, overbets are not consistant with someone having a set and trying to draw the maximum chips into the pot. They more likely indicate a moderate stentgh hand going for a quick win or a bluff.

More than half the time I think I'm calling!