The route via Yakima/Kennewick/Boise/SLC then east to Cheyenne and south on 25 is the one I would trip plan. Agreed on Wyoming winds. You can also look up altitude changes, and there is likely a map showing grades as a cross section, somewhere.
Truck drivers use 50-mph as a way of calculating travel times. I recommend it. In fact I would use 47-48 mph as a more accurate way of planning stops included in that travel time
. Estimate fuel consumption as high (8-mpg), and keep the need to get out of the truck every two hours to stretch and inspect rig as a given. Do some number crunching, and have stop names/exit numbers to hand before setting out. ("126 miles to Big Joes Truck Stop at Exit #346" at 2'17" travel time [58 mph]. Then, the next. And the next).
Use GAISMA to determine civil dawn and twilight for departure and arrival times. Leave early -- just a little -- but be off the road well before
dark. Days are only about 9.5-hours this time of year that far north (we have more time 2,000 miles away, and south), so don't give up any margins considering weather, traffic and the rest. And one loses an hour in transit due to time zone.
Daily travel times may be short and prep is all about what is done the day before (rig, fuel, food, clothing, etc).
Google sez 25-hours for 1,577-miles at 63 mph. I would say -- more reasonably -- 34-hours when stops are included (47 mph). Call it three nights on the road or 450 mile/day average. One may do better, but it is not the point with  an old truck  a trailer  and an easier return trip. I would give myself a week for the roundtrip, and re-calculate once at Cheyenne on the outbound leg.
3,200-miles in a week is a LOT of miles. Even for a professional driver. Winters onset only makes it more important to plan each day in advance.
Good mirrors are everything. Have truck rear brakes adjusted
, and keep all glass spotless at EVERY stop! Start today with all new signal and head lamps on truck & trailer. A heavy duty flasher. Read up on hitch rigging and find a weight scale to dial it in. Tires, etc. Read around.