Welcome!

There are pros and cons to both. I-94 is about 1/2 hour faster according to my mapping software, but that doesn't account for possible delays getting through the Twin Cities in MN.

Either way, 3 days is possible, but it will be 3 pretty long days - 600 miles, which would be somewhere between 10 and 12 hours, depending on how fast you want to drive that brand new truck and how many stops you make.

If you take I-94, my software breaks up the overnights to Fergus Falls MN and Custer MT. However, from a practical standpoint, you would want to make that Fargo ND and Billings MT, both of which have a wide selection of hotels to choose from.

If you take I-90, your first overnight would be Sioux Falls SD (large selection), the second would be Billings.

You won't have any problem finding fuel either way - and as a matter of fact, I-94 is less traveled than I-90.

Which would I choose? I think in this case, it would depend on the river flooding status at the time.

If your new truck is a diesel, make sure you start the trip off with a full DEF tank. The most economical way to do this would be to find a truck stop that has a bulk dispenser, it's a lot cheaper than buying gallon jugs.