I often travel 93 over Lost Trail Pass in a car and have often thought about a side venture on 43, but so far I haven’t taken the turn.
The highway to Lost Trail from the North is a bunch of Up. Nothing scary, good road, plenty of room, rest area at the top. As long as your rig is good for climbing you’l be fine. From the top down toward Challis is down, down, down on a less well maintained road, plenty of curves and. plenty of low gear go slow areas. You’ll have a great ride on your bikes.
The ride from Challis to Stanley is beautiful so I suggest you extend that run just a bit farther… and the ride to Ketchum is mighty fine too…
How’s that for not answering your original question! There is just so much greatness to see in that area.