Yeah, Priest Lake sucks....
We have been there 3 times this year. The weather is always tricky. the lake is big and storms do come up fast. but the sand bar (north of coolin) and the resorts (cavanaugh's, etc) make it worth it.
My suggestion, is if you have a place to keep the boat on the lake, then take it. if not, then it becomes a little bit of a challenge to get the boat out of the lake if a storm does come in.
Definitely a great place though.