Welcome to the RTA Forum!

In general, the best route for a winter trip is the shortest route. That keeps you on the road for the least amount of time, giving you less days where you could see a storm, and the most time to wait for conditions to improve if you do see bad weather.

In your case, I-80 or I-90 are about the same distance. I-90 does cross the mountains at a lower elevation, and is often one of the better choices, especially because I-80 across Wyoming can see high winds, which can make it tough to tow and adds to problems of winter travel. However, having said that, I would still make my final decision based on the specific weather forecasts at the time of your trip. It's possible that I-80 could be clear while, I-90 is seeing a storm - or vice versa.

Also, considering you are towing, I'd try to avoid the tollways if possible, as they can get quite expensive. Depending upon exactly where in PA you are starting from, that will likely mean going down to I-70 across Ohio and Indiana, then using I-74 to get back to I-80, and take that across Iowa. Once you get to Western Iowa, you can decide if you'll be better off sticking to I-80, or using I-29 to catch I-90 in South Dakota. Of course, if there is bad weather in the east, then you might want to look at other options too.

Again, depending upon where in PA you are starting from, this trip will take you at least 5 days to do it safely, but I'd try to have at least 6 or 7 available just in case the weather turns against you.