WY 22 west from Jackson (Wilson) you climb steadily for quite a long time. At the peak of the pass you will then start decent to Driggs, ID. Slope going up and down is or exceeds 10% for good long stretches. Sharp switchbacks and few pull outs available. Gentlest way west would be W. Yellowstone US 20 to Idaho Falls or even west US 26 from Jackson to Idaho Falls. US 26 follows the Snake River through the mountains, little elevation change.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI