10/20 Live Bellagio River Full House

[IShearSheep]

Villain is older gentlemen, 60ish who plays regularly at the Bellagio during the day and wears a cowboy hat. I have chatted with him quite a bit in the past few days and played several hours with him. Seems very ABC pre and post and I can't recall him ever being out of line. I have 4800ish to begin this hand he covers.
Live 10/20 9 handed. UTG limps, I limp UTG+1 with 4h4d, villain limps UTG+2, MP limps button limps as well as sb and bb.
Flop: 7s4s2d, checked to me I fire 140 villain calls button
calls all others fold.
Turn: Kh, I bet 460 villain raises to 1000 button folds I tank and call.
River: 7h, I check and he immediately says all-in. I have about 3500 left. What do I do? FWIW, when he raised me on the turn I was 99% sure he did not have KK because I had never seen an instance where he did not raise qq kk aa pre from any position and saw him do it quite often from utg and early positon.