Beautiful places to trip across the country?

I'm doing a 2-3 month road trip from Florida to Oregon. (I'll hit up Texas, California, Colorado, Arizona to name a few). Where do you recommend I trip? I plan on taking very manageable amounts (1/4 tab up to 1/2 tab) since I'll be solo for much of it.

Grand Canyon is on there. Any other tips and/or places I should see?