Great American Roadtrip tips?

I will be leaving Maine (Where I live) in September 2018 to explore in every state. My plan is to spend at least 3 months on the road. I am female, traveling alone and will be 21 when I leave. Haven't decided if I want to rent an RV or just travel in my reliable 2012 Honda civic. I've done quite a lot of research and preparing but I am hoping for honest opinions. Tips for safety, places to stop, sleeping, price point or anything you think may help is what I am looking for.

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