Are there showers at big meadows? If so, is there a cost?

Yes, there are 8 private shower stalls. (In same area as the laundry and small camp store for firewood). There's a small parking lot, too. The cost is 7 quarters, I believe, for about 5 minutes of hot water. You just put quarters into a box inside the shower stall and the water turns on. I think I saw a change machine, too. I recommend showering in sandals (flip flops). Each stall should have a small bench, too.

Yes . Some of the better ones we had this summer.

There are showers available. Not sure what the prices are, but I think it's a couple of dollars or so.