There is a laundromat located next to the smaller swimming pool, which is near all of the cabin loops. It is open 24 hrs, but you need a cabin room key to access after midnight. I don't know if there is another one where the camping loops are.
The washers are $2 per load. The dryers give you 15 minutes for $1. The max you can put in a dryer at any time is, IIRC, $4.
There are change machines in the laundromats, but we brought quarters with us - For some reason, change machines never seem to work when I really need them.