My group sounds very much like OP's.
Many players willing to call til river to hit runner runner flush or straight or 2 pair.
My table image is that I mostly always play 2 face cards, good pairs, suited connectors such as 89.
I've been playing more aggressive lately, similar to
@Kain8 's comments. And it's been paying off with multiple 1st place, 2nd place finishes in our Pokerstars tourneys.
Also, pretty much every game I have been chip leader at the halfway point.
When facing limpers, I've been raising 3-4x BB + each bb limp. Usually that narrows the sb, bb, 2 limpers to 0 or 1 caller. Sometimes 2 but not veryboften at that price.
Continuation bet on the flop+turn will win me a huge majority of hands. I rarely get to river or need to showdown.
The 1 thing I've changed though is my postflop bet size. Where I used to bet the pot, or 3/4 pot, I'm finding that 1/3 pot has the exact same results lately. Not sure if that will continue to be the case, we'll see.
The crazy caller will call no matter what. So why risk a pot size bet when 1/3 will do? If he hits his out and starts raising into you, it's much easier to fold.
But with a similar group as OP and Kain8 example, I'm winning about 70% of the hands on the flop, or turn. The ones that called to the river, and the river card is a flush/straight maker, this is where I'm no expert so I'll stop here lol.