I-80 Wyoming in a Box Truck

Are you leaving soon? Looks windy in Wyoming over the rest of the week. Colorado and Utah look good for the next three days at least. I-80/I-76/I-70/US-6/I-15 is the way I would go.

 

Well, I-70 will take you though the heart of the Rockies, with a lot of curves, steep mountains, and not a lot of affordable places to stop. Nice to see in your car, not a place for a rookie driver with an overloaded 6-wheeler to drive. Especially if it snows. You'll also have to get through Denver, first.
The biggest issue with WY is wind. Stop at Little America when you go past it, and be careful crossing the Wasatch range, especially if it snows. You should limit downhill speeds to about 40-45 mph, gearing-down when needed.

 

Actually, ex-Trucker Alex is right. You probably don't want to be crossing the Rockies in a rental van and a trailer, even if the weather looks good. You can bypass the section of I-80 that gets bad winds and icy road between Laramie and Rawlins by taking US-30 in Laramie to Walcott Junction. Only adds 15 miles or so. Looks like some weather moving into Wyoming Friday and Saturday, though. Don't know what to say about that. This isn't the best time of year to be driving across Wyoming and going the southern route and avoiding the Texas Panhandle will add about a thousand miles.

 

Keep in mind, not only will your rig be heavily loaded so that climbing a steep 6% grade will likely slow you down to about 35 mph, but you are also gaining elevation. At 10,000 ft, you will have lost at least 1/3 of your power just due to the altitude. You may end up climbing at as slow as 20mph, revving at max RPM, possibly overheating your motor. Then you have the downhill. I wouldn't even CONSIDER driving such a combination unless the car trailer also has trailer brakes and a stability coupler. And, trust me, you will NEED to descend those mountains at a slow speed as well, lest you smoke your brakes and end up an out-of-control rocket heading downhill at 80 mph into the nearest escape ramp. I grew up in Boulder, and I have 1 million + miles driving experience on large trucks. I would choose the Wyoming route 100%, without exception for your trip.

Also, keep in mind that there are big wildfires in the Texas panhandle right now. Also, an extra 1000 miles will set you back at least another $500. I 80 goes STRAGHT to SLC. Just deal with the snow, it's the safest route. If you have to wait out a closed highway for a day, you'll still arrive in SLC before you would going south, or breaking down/crashing in the mountains.

 

I doubt the OP will ever post here again, but if he got past Rawlins, he's good all the way to SLC. Laramie to Rawlins, however, has a high-profile vehicle ban on both I80 and US30, though, due to winds. Still, you could just rest-up in Laramie, maybe even overnight it, and they'd still be better off than having to go through Albuquerque...
Colorado on I70 is wet with icy spots from Georgetown to Vail, with slowdowns only on the uphill climbs to the steepest passes.