KOA on SPI has a hot tub and pool PLUS there is a free shuttle that goes anyplace you may need. Lot's of walking and biking for those that enjoy it. County park is cheaper, but no real facilities to speak of other then FHU and cable.
Permanent RV's are not allowed in either park so you will be among other mobile RV'ers if that's what you like. Nice way to pick up other places to stay and go to on the migration path.
Whatever you do don't book long term if you can afford it. The reason why you get a cheaper rate is because (IMO)after a month or two you would move on otherwise if you weren't locked into that park/area.