Honeyman park is close by and easy to get in/out. It's located south of South Jetty. Further south is Driftwood II OHV Campground, but do be aware this is a popular campground and without a reservation it could be tough to get in. Plus this is a popular offroad campground, so go in knowing there will be a lot of ATVs. During the off season Honeyman allows ATV campers but only in the H Loop and between now and October they are not allowed.
If you're into the casino thing THree Rivers Casino offers free camping, this is from their website. "We provide free RV parking at our casino in Florence and Coos Bay! Join our Players Club and get 4 days and nights of Free RV parking, then you can earn 100 points on your free club card and get another 4 days and nights free."
