I am going on a driving trip for a few days in OHIO. May 13-May16. What is interesting to do? INEXPENSIVE!!!?

My sister, her best friend, and I are "escaping" for a few days of relaxation. drive, camp, sight see, take photos, antique shops, low budget, JUST OUT FOR FUN. We will be in OHIO. This is the first time I've been able to go with them. they usually go for a long week. this time they have only a few days free. it fits my schedule so they invited me along. I have not quite a week free between college sessions. this will be some much needed "fun" time for me. AND I will get to spend time with me sister, who lives in a different state than I do. Oh! and they rarely travel on main highways. they like to go exploring off the main thoroughfares.