For what it's worth, last year I made a short notice ride up to Sturgis from Utah. We stayed with a friend in Buffalo, WY the first night. The second night we found a campground outside Rapid City. There was space in the first place we checked.

I think most commercial campgrounds will find room for you, especially if you get in before sundown.

 

Most Wal-Marts stopped allowing overnight parking in their lots. Too many customers complained about the bums....LOL


OP: You will be fine since you can camp primitive. There is always someplace to do so. All over Idaho there are free camping spots that don't have anything but a patch of grass.

 

I've always wondered about pitching a tent in a wooded section of the median strip of an interstate. Just into the woods, drape a camo tarp over the bike.

 

KOA's work out nicely. There are a lot of them even outside of larger cities/towns. A great resource is an app called ALLSTAYS camp and tent. It lists everything from private campgrounds to BLM land and is gps based so when you get tired you can look and see what's around and ride to a spot. I've used it on a few trips now and found it works great.

 

Did that once. It was awfully loud with traffic.

 

I found KOAs a good option in the US on my trip last summer. Showers, wifi and good people to meet and normally close to good places to eat, I don't haul cooking utensils. Just added the KOA and AllStays Camp and Tent apps to my iPhone for the up coming season as well.

Also trying out the GreatestRoad app to find the best roads and attractions once I get to my intended destinations.