Ketchum to Jackson

I did not have the same experience as the previous poster going over Teton Pass from Jackson towards West Yellowstone two summers ago. 10% max grade with a 1-ton SRW diesel and 9000lbs 30' TT in tow... so I did have the advantage of an engine brake. Since it was summer and warm at the time, there was zero chance of any ice. Yes, you want to take it slow as there are curves within the steeper sections of the road but the worst part of Teton Pass, going in the direction I traveled it, didn't seem to last for too long. Based upon all the danger warnings I pre-read about Teton Pass, I expected worse. It's not a pass to take lightly but I would have no hesitation going over it again with my combo so long as there was no possibility for ice.

Maybe it is worse travelling it from Idaho to Jackson???

Do not take Teton Pass. It's extremely steep and not worth the chance. We did it once towing a 17' TT and were scared out of our wits and that was before we knew any better. We travel from the Boise area frequently to Jackson and beyond and we always take 26 to Alpine Junction and take 89/191 into Jackson. It's a much better ride.

Yes, driving through the park is not a problem. The roads are good and any of the elevation changes going over the Continental Divide feel minimal. You can always do the reverse by taking Hwy 20 into West Yellowstone, go through the park, then down to Jackson. You will climb Ashton Grade but it's doable. Looks scary when approaching it, but it's not really that bad - way better than Teton Pass.