Yes, the upper ones are big, suitable for the biggest rigs. Farthest from the river, though.

A few of the sites should be long and wide enough. The shady sites along the river are definitely going to be too small but the sites in the open away from the river should work just fine. All sites are level and few trees or other obstacles to worry about.

Yes, there are several.

There is open long pull through site which might work (check the satelite view). It's a small campground. Walk through first to make sure you feel comfortable with it and that the site is available.