Replying to Senior Year Capstone/Graduation Road trip

Me and my buddies concocted a plan today that for one last shABang we take a road trip to some where awesome. Money is definitely a limitation. We are going to drive my friends van, and each pitch in for gas. We plan on camping at all the stops, or somewhere close by. I know we couldn't afford hotels. The question is, where to?

We live in Northern IL, about an hour outside of Chicago. I have seen a lot of the national parks out west: Yellowstone, Grand Teton, zion, arches, etc. But I'd like to do it again. One of my buds had described a more destination trip to Maine, thoughts?
I definitely thought a loop out west with several stops along the way would be awesome.

Does anyone have any experience with this? Dos and donts, etc? Awesome places to see? I have Mt. Timp on my list for sure, but what else. Trying to get other opinions and ideas.
This is in the very beginning stages and nothing is by any means well thought out, yet..

Also, we were thinking about going next summer, mid-late july, maybe around 1.5-2 weeks. There will be 4 to 5 of us. And we will all have just graduated high school so we'll all be 18.

Hoping to stock up on ramen, granola, and brews for around a campfire before we leave. Here's to showering in a mountain stream, and living freely for a short stint.

Anything/thoughts are appreciated.
Take it easy
Think snow