raise, call, or fold? trips hand

[knifeandfork]

7 hnded live 5/10 nlhe game is unusually tight passive today
UTG(900) limps folded to sb(1500) that completes i check Ad4d in the bb(900)
flop is
Qd 4h 6s sb checks, I check, utg checks,
turn is
4c sb checks i bet $40, utg folds, sb raises to $100 i ponder briefly and call
river 9h
sb leads $300....?
comments on turn play and what to do on the river appreciated.
jason