Welcome to the RTA Forum!

It looks to me like you actually have already got a good start. You know about how long you have and you know the siteseeing, and seeing unusual things is a big part of your goals. Now you just have to work out the specifics.

Working out the specifics can be the fun part of planning. There are lots of choices of things to see, so you'll really have to narrow things down. This part of the RTA Site focuses on the oddities, and here is a list of thing to do in every state, and those lists just start to scratch the surface. With 7 days, most of the east coast and the midwest are really within your reach.

As far as your car, renting a car could save you some money, especially if you factor in the wear and tear of putting additional miles on your own car. But you'll have to shop around to find how much a rental car will cost for your trip, and if math works out, so to speak.