Anyone ever have an issue with campsites (National Forest, mostly) being full? Some of the campgrounds we'll be planning stops for are pretty small (~20 sites), and we'll obviously be getting in a bit later than some of the car campers. I can't imagine being turned away if you're on a bike and it's late in the day, but you never know...

Thanks for any info!

Some of them have overflow areas for tent camping.

You might check, but National Forest areas typically also permit dispersed camping -- away from established sites. We've had some of our best camping experiences heading down fire roads and off into the bush a bit. No neighbors, no noise. We dry camped at one off Minarets Road in the Sierra. We saw not a single person over two days, and had a sweeping view of the Sierra crest. It was a dry site, so we had to hunt down water, but it was great.

State parks -- at least in CA and OR -- often have hiker/biker sites that are available to whomever wishes to drop in (hikers and bikers only) and no reservations are required.

My experience with the national forest campgrounds is that on the few occasions they are full, someone will let you share a site with them. Lots of people travel in RVs and aren't even using their tent pad & picnic table. Just ask, and definitely offer to pay or share the fee.

You can also approach the camp host and ask if they can help you out, I don't think they have to, but they usually do.

If you are a big group, this might not work for you, but for one or two people it probably will.

I'll second the asking of the camp host if full for help.... I've had park rangers set me up in out of the way places when no space was available. I think most the time it's out of pity after seeing how tired I look. And like mentioned if this doesn't get you a spot just ask a few RV'rs to take pity. Most campgrounds are full of super nice people willing to be helpful if asked.