Best Approach to Yellowstone?

[mkcurran]

Trying to plan a trip to Yellowstone with our 36 foot class A and a toad on a dolly. We'll be coming in from the South, from I-15. How is highway 20 for getting to West Yellowstone? We'd rather not hit windy roads or too much of a grade.
Would we be better off going up to I-90 and dropping south from there? Looks like that move will add at least 100 miles onto the trip.
Thoughts?

[BarryG20]

You can catch 20 off of 15 in Idaho falls takes you to west yellowstone

[westernrvparkow]

Where are you staying when you get to Yellowstone? It isn't just a point on the map, it is bigger than Delaware and Rhode Island combined.

[Lwiddis]

All the entrances to Yellowstone are beautiful. I never leave by the route I arrived.

[donkeydew]

good road you will have no problem.

[azdryheat]

Nothing wrong with the 20, it's approved for 18 wheelers.