There are 128 tent sites with water nearby... Online they have a map of the sites, with info on site length for each site. Just because it is labeled as a tent site doesn't mean that RVs aren't allowed, just no hookups for them. Tent sites are also cheaper. At popular parks RVers will get a tent site just to get in. Also, Oregon has just announced a surcharge on out of state visitors, details on their website. Also all beach campgrounds are by reservation only .

Absolutely

Current info here: https://stateparks.oregon.gov/index.cfm?do=park.profile

Yes and there are yurt rentals too.