Hello Jen - Welcome to the forum. I hope you find the answers here with useful suggestions to route you where you're trying to go. I have family in Idaho and our daughter lives in Wyoming, but I don't have enough experience near the Tetons to give you any specific advice.
I can give you some general feedback though. As a guy who watched way too much TV in the 60s and 70s, I grew up believing that it was inevitable that we were going to end in a firey crash at the base of the ravine. It happened at least once per hour every night on prime time, right? So I can feel your pain to an extent.
As an adult driver, my phobia isn't so much going off the edge of the road. My phobia is that I'm going to blow up my truck on a steep grade. (Probably not at actual phobia level, but let's call it a dusting of angst.) If there's a wider, flatter route, and we can travel that way without really missing something scenic, then that's the route for me.
The best tool I've found for this is Google Earth. Once I've mapped out a proposed route in my head, I can launch Google Earth and simulate the drive to see what the topography looks like. This gives you an amazing preview of the terrain, and you can quickly see whether your route will take you through switchbacks on the side of the hill or a lower road at the base between two tall hills. Those are two very different experiences. I don't do this very often, but it has always been helpful when I have.
Last February we stayed in the middle of nowhere in southern New Mexico, near a town called Rodeo. This was the closest camp to the POI we wanted to see, Chiricahua National Monument in eastern Arizona. As the crow flies, it was pretty close, but the actual route was going to be about three hours to get around the hill. The woman at our camp gave me a hand-drawn map with a short cut to get there. It turned out to be a pretty hellish drive with snow and ice across this one lane dirt fire road (with no barriers). Luckily my truck has 4WD, but this was really no road for a long bed dually. My wife and daughter thought this was a great adventure, but I was pretty tense by the time we got there. For all that effort and risk, it still took us hours to drive that "short cut". We had the time of our lives exploring Chiricahua, but when we were done for the day, I didn't even hesitate to take the interstate back to camp. It was a great adventure though and a fun memory. My wife and daughter like to give me hell for it still: "Remember that sketchy road in New Mexico? Remember how uptight you were?"
Yeah. I remember.
Good luck to you and I hope that you're able to find the routes that will bring you joy instead of dread.
