KK - Overpair + Flush Draw Faces Odd Turn Donk Multiway

[SixForty]

I know this is a big pot, but how often am I actually going to win this here?

Live 10/20, 10-handed - nice and juicy loose/aggressive game

Reads:
SB - after about 4 hours at the table, he seems to be pretty downright average and relatively straight forward, I don't recall him getting out of line very much at all
UTG+2 - semi-tight/semi-passive, she's an older lady that I play against every now and then, maybe once a week or so, I'd say that she used to be tight/passive, but she seems to be getting better lately, and playing a little bit more aggressively, but her preflop capping range is still very tight
MP2 - loose/passive, pretty much your standard calling station
MP3 - unknown, only been at the table for about 3 orbits, nothing out of the ordinary yet

Preflop: Hero is CO with K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img]
<font color="#666666">2 folds</font>, <font color="#CC3333">UTG+2 raises</font>, <font color="#666666">1 fold</font>, MP2 calls, MP3 calls, <font color="#CC3333">Hero 3-bets</font>, <font color="#666666">1 fold</font>, SB calls, <font color="#666666">1 fold</font>, <font color="#CC3333">UTG+2 caps</font>, MP2 calls, MP3 calls, Hero calls, SB calls

Flop: 8[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/club.gif[/img], 3[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(5 players, 21 SB)</font>
SB checks, <font color="#CC3333">UTG+2 bets</font>, MP2 calls, MP3 calls, <font color="#CC3333">Hero raises</font>, SB calls, UTG+2 calls, MP2 calls, MP3 calls

Turn: 9[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(5 players, 15.5 BB)</font>
<font color="#CC3333">SB bets</font>, UTG+2 calls, MP2 calls, MP3 calls, Hero calls

River: 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(5 players, 20.5 BB)</font>
<font color="#CC3333">SB bets</font>, UTG+2 calls, <font color="#666666">MP2 folds</font>, <font color="#666666">MP3 folds</font>, <font color="#0000FF">Hero . . . ?</font>

I can't imagine that I'm good here very often at all, but getting 22.5-1? With the semi-tight/semi-passive in there, can I overcall? Should I lay it down in this big pot, or is it fur coat theory time?