It depends on how old the SP is, and they don't tell you. We did the Oregon Coast last season and stayed almost exclusively in State Parks. The only one we had trouble with was Harris Beach, just north of Brookings. I guess that park pre-dates 102" wide rigs with slides and was designed for 30' or so length.
We found the roads in the park to be narrow and the sites were square on to the roads. Backing even our 32-footer (102" wide) was dodgy. I used an unoccupied tent site, opposite the site we'd chosen, to set up for backing in. Unfortunately, I didn't see a 24" or so high rock wall on the sidewalk side of the rig. DW was on the driver's side making sure I didn't hit the picnic table and I scrunched three stow-bin doors on the RH side against the wall.
Not serious damage, mainly scratched paint. If we hadn't decided to sell the MH, I wouldn't have bothered fixing it for now.
All the other OR SP's we stayed at were fine, but we were a bit disappointed how far we had to walk to get to the beach at Fort Stevens (we don't have a toad).