You may want to read up on 'boondocking' -- camping (legally) without a campground :). That's what you saw near Goblins.
You usually will not need to empty and fill tanks every day, and you can do those things at gas stations, day use areas, etc. Your RV will charge your batteries while driving.
You can camp on most (used to be all) Federal and State-owned land for free. Maps are available, and this forum and ranger stations can suggest extra-nice spots. Forest Service and BLM campgrounds are also great for RVs, especially if yours is not huge, and are very cheap. Some of them have electricity or dump stations or plentiful water, others are more rugged.
National parks are amazing, but they are not the only beautiful places. And you can often camp or boondock outside the parks and drive in for the day.
