Who's the bigger donk?

I needn't remind anyone about the dangers of a paired board. But what can prove deceptively perilous is when the river card pairs the turn card. Following is a hand in which I played worse than the donkey I was up against.

Full Tilt Poker Game #2177715576: Table Antigua (6 max) - $0.25/$0.50 - No Limit Hold'em
Seat 1: jaballthehut2 ($49.75)
Seat 2: HomelessShelter ($97.40)
Seat 4: beavrliquor ($76.50)
Seat 5: k4750 ($19.45)
Seat 6: ALP-TOR ($73.65)
k4750 posts the small blind of $0.25
ALP-TOR posts the big blind of $0.50
The button is in seat #4
*** HOLE CARDS ***
Dealt to HomelessShelter [3c Kc]
jaballthehut2 calls $0.50
HomelessShelter calls $0.50
beavrliquor calls $0.50
k4750 folds
ALP-TOR checks
*** FLOP *** [3h Ks 9d]
ALP-TOR checks
jaballthehut2 bets $2.25
HomelessShelter calls $2.25
beavrliquor has 15 seconds left to act
beavrliquor folds
ALP-TOR folds
*** TURN *** [3h Ks 9d] [5d]
jaballthehut2 bets $6.75
HomelessShelter calls $6.75
*** RIVER *** [3h Ks 9d 5d] [5h]
jaballthehut2 bets $20.25
HomelessShelter calls $20.25
*** SHOW DOWN ***
jaballthehut2 shows [Kd Jc] (two pair, Kings and Fives)
HomelessShelter mucks
jaballthehut2 wins the pot ($57.75) with two pair, Kings and Fives
*** SUMMARY ***
Total pot $60.75 | Rake $3
Board: [3h Ks 9d 5d 5h]
Seat 1: jaballthehut2 showed [Kd Jc] and won ($57.75) with two pair, Kings and Fives
Seat 2: HomelessShelter mucked [3c Kc] - two pair, Kings and Fives

There was no point in calling the $20 river bet, since I had to give him credit for at least a king. Once the 2 fives popped up and my 2 pair were counterfeited, there was a good chance his higher kicker would come into play. As for the flop and turn betting, I believe that he thought he had the best hand throughout and I wouldn't have been able to raise him out of the hand. I still should have raised though.