My two experiences might not be the most helpful as either not recent or not with teens, but thought I'd share -
As a child we did a lot of motorhome holidays on the West Coast - a lot of fun and so much to do, and you can split between city and nature. I can't say for economical, I imagine it's quite expensive now. There will be loads of sample itineraries online, but core memories for me were (I don't think we did these all in the same trip...!)
- Yellowstone National Park
- Grand Canyon
- Wyoming - we stayed on a ranch, did pony trekking etc.
- Disneyland
- Las Vegas
- Joshua Tree
katie_ellison on instagram did a USA roadtrip in Jan, worth looking at their trip
We have also been to Canada to visit family - if your'e doing a driving trip in Canada it can be A LOT of driving depending where you are going. East Coast is great lobster and seaside towns, but we really loved Vancouver - lots to do in the city they you could either rent a van/car and head to Vancouver island (Tofino was a highlight for us) or a cruise in Alaska (haven't done this, but considered it, incredibly scenery.)
If you're in Vancouver, you can then go over the border into USA to Seattle or Portland which are both cool cities with a great food scene.
Not super detailed, but hopefully some ideas to get you started!