I have found that on some routes that is pretty easy to manage even when riding alone.

On the Pacific Coast for example it was easy to fall in with an impromptu group of new friends. On the Trans America, we didn't camp with the other cyclists as much, but still did still make good friends with others on the route and did camp with them some of the time. On the ST I met fewer other tourists, but even there did hang out with other cyclists. On routes where I didn't meet many (or any) other cyclists I typically met other folks who were either locals or were car camping.

I don't think I ever did a tour where I didn't meet and hang out with others at least some of the time.