If you've been traveling for a while and are needing a free place to stay, Colorada has some options that just might be perfect. RV camping can take place on land that is public and maintained by the US Forest Service as well as the Bureau of Land Management. You might want to research online or call ahead to make certain that nothing has changed.  There are also several state parks that do allow some free RV camping, too but again, verifying the options before arriving is always a good idea.