I lived near both I-70 or I-75 during my entire life. A bit to say about both
I-70:
- Both termini of the highway. I know some people hate it for ending in the middle of nowhere on one end and a parking lot in the other, but I find it unique
- Breezewood
- The part west of Denver seems like a nice drive.
- It's the successor of US 40, a US route loaded with history.
- A nice variety of cities it goes through or near, like Denver, Kansas City, St Louis, Indianapolis, Columbus, Pittsburgh, DC and Baltimore.
- Probably one of the interstates that we debate about its control cities the most here, from Limon to Baltimore Beltway.
I-75:
- 6 laned for a good chunk of its route, though that's sort of because of its high truck traffic.
- Successor of the Dixie Highway (US 25 in the Midwest and US 41 in the south).
- Mackinac Bridge