Best route Provo, UT to Grand Tetons - Help!

The best route is the Google Maps suggested route from Provo to Evanston, then to Alpine, WY, and along the Snake River into Jackson.

Take the 80 to Evanston, and then the 89 north to criss-cross across the Idaho border until you get there. It's a pretty drive.

I just put it in google and got a very decent route meeting your expectations I believe. You will have to travel 16 up to 89 (US Highway) and then US 191. The "sketchiest" part in relation to your criteria is 16. But, Take a look at some random spots on 16 on google street view, and you will see it is not heavily traveled pretty wide with shoulders...

That seems like a relatively easy day trip... IF you have somewhere to land. Frankly Jackson sucks...for air... There is a place (Headwaters/Flagg Ranch) in between the Tetons and Yellowstone that isn't cheap but has full hook ups and quite a few and is NOT a parking lot if you know what I mean... Makes a decent base camp. the dirt road west can be fun also.

Google Maps has 3 routes all within 34 minutes of each other. If mountains bother you stick to the Interstate routes. For me, I'd take the most direct route as it's also approved for truckers.