#2 and #3 would be the same once you hit I-84 at Fruitland. The roads are both good. Of course, #3 would be freeway the entire way. If you choose either of those, wave at us as you go through Fruitland!
Highway 93 will take you over Lost Trail Pass, through Salmon and Challis and then through the Craters of the Moon National Monument. Those are two lane roads, but well maintained. Large trailers have no problem with Lost Trail...in fact the mega loads bound for the Alberta tar sands project took it.
You can also take Highway 75 from Challis through Stanley and then in to Sun Valley. That is also a winding road, but has some of the most spectacular scenery in Idaho.
Stanley and the Craters are also easily accessible from the Sun Valley area and make good day trips.
Enjoy your trip!