This is one of the best written and thought-out posts I've read in a long time.

In addition to having toll-free numbers for each state's DOT (such as 800 226-7623 for Montana) road conditions can be obtained in most states by dialing 511. (Sometimes there is one 800 number to call from out of state and another 800 number for in-state.)

As you said, "no one can predict the future," and, this is especially true in the mountains you will be traveling through in Montana.

I would be prepared for an emergency with water, food, blankets, etc.

I would carry AAA Tour Books and/or telephone numbers for motel chains such as Hampton Inn 800 446-6677, Best Western 8000 782-9422, Holiday Inn 800 465-4329, Choice (Comfort Inn, Quality Inn, etc.) 800 521-2121.

I wish you a safe trip.

HTTY

Agree on carrying blankets, food and water. Make sure you are also carrying a sturdy snow shovel and something to use in case you encounter ice (kitty litter? salt?). Also - never let the gas in you tank go below half - in case you encounter bad weather and/or closed stations.

Check the wether forecast carefully each morning - and don;t be cowboys. A big difference between driving this route and in MA is the distance between safe places to stop. You can;t assume you will come on a refuge in the next 5 or 10 miles - it may be much farther than that.

Wind can also be a huge factor since there is nothing much to stop it until you get to East Glacier. Wind means drifting if there is snow and fighting the steering wheel if there is not.

Good advice above. Make sure you have warm boots and mittens. Stay with the car if you have trouble.

You are really creating your own likelihood of good luck by being prepared.

All good advice above. Are you driving a rental car or the car of one of your drivers? The most secure way to get from MSP to SPK is on the Empire Builder (Amtrak). Three of you can ride in coach for about $500/3. The trip on Amtrak takes about 29 hours.
Keep in mind that large areas of Montana have spotty cellphone service.

Thank you all for your advice. I had not considered the impact of wind. Unfortunately, Amtrak's Empire Builder is not an option because we are driving my car.

I have now come up with two possible routes:

Route A
1/23/2012: Minneapolis, MN to Miles City, MT (695 mi, 10.8 hours at 65 mph)
1/24/2012: Miles City, MT to Spokane, WA (684 mi, 10.75 hours at 65 mph)

Route B
1/23/2012: Minneapolis, MN to Bismarck, ND (426 mi, 6.8 hours at 65 mph)
1/24/2012: Bismarck, ND to Bozeman, MT (558 mi, 8.5 hours at 65 mph)
1/25/2012: Bozeman, MT to Spokane, WA (399 mi, 6.5 hours at 65 mph)

I would prefer Route A due to its shorter timespan, but is there a compelling reason to choose Route B instead?

Thank you,
Basil

If I were you, I would plan to make the trip using Route A but also prepared to change course if road conditions require it.

In other words, I would not set out on Route B assuming it is a safer bet than Route A because Route A may be passable when Route B is not.

HTTY

Your routes are the same whether you use A or B; you're just giving yourself an extra day for travel which is smart.

I used to travel between Fargo and Butte, MT in the winter. You could have great roads, and you could have closed roads. Be prepared to take the extra day. Your worst roads will be in ND, and then the Livingston Hill between Livingston and Bozeman. You'll likely hit bad roads again over Lookout Pass between Missoula and Spokane. You are running interstate the entire way, and the road crews are pretty good at keeping the roads sanded, especially the mountain passes.

As mentioned you will need emergency equipment shovel, blankets, kitty litter, food, water.

Do not stick to just this route because if storms are coming in from the north then it might be better and faster to take the freeway.

I have not driven much of the Dakotas, but I am very familiar with Montana which is where you are going to find the larges passes. Pay a great deal of attention to the road conditions on Lookout Pass as it will be your largest pass.

However, if the weather doesn't change much in this area (Idaho-Montana) then it will be a slam dunk because we have virtually no snow.

Basil, my two cents worth
1. Buy and wear long underwear once you land at MSP. The temperature will feel much cooler than Massachusettes.
2. Pack a couple of candles and matches in your car, and a charged up cellphone. Reception is spotty but usual.
3. Hotels are booked up in Montana and North Dakota.(oil boom) We stayed in Glendive Montana in a neat bed and breakfast called www.charleymontana.com . Bismark should be fine for hotels but check before leaving.(bad reviews on TA)
4. Stick to the freeway. Stick to the freeway. Stick to the freeway.
5. If the visibility gets too bad, the highway patrol will shut down the roads. Period. It is always windy in North Dakota.
6. North Dakota has the best roadside restrooms.
7. You may not average 65 miles an hour, wind is your enemy as it blows snow accross the freeway and makes slippery spots.
8. Enjoy your trip. You are about to see some of the friendliest people anywhere.

I would choose route B to give yourself extra time. Consider that sunrise is going to be around 7:45-8 am, with sunset around 5:15pm. That's 9.5 hours of daylight plus dawn/dusk. Personally I hate driving on potentially snowy/icy roads in non-daylight hours, just makes it harder to see any issues. So I would make the trip in 3 days just to restrict driving to daylight hours.

<<Do not stick to just this route because if storms are coming in from the north then it might be better and faster to take the freeway.>>

Both A and B are the same routes, just 3 days instead of 2 days. It's all freeway.

Good News - ND is experiencing (so far) the mildest winter on record, with just a trace of snow.

Bad News - This could change at any time.

If conditions continue as they are for the rest of the month, you will experience little to no problems, with the exception of room reservations. I would suggest making reservations; check to make sure you can cancel them by a certain time "day of", in case the road conditions change unexpectedly. I-94 is good at clearing snow/sanding roads quickly. The problems you may encounter could be "black ice" - icy roads that are polished by snow blowing across it, or gusty winds, which can either cause you to slow down due to slippery conditions, or cause limited visibility if it snows.
Best Suggestions for winter driving in Northern Plains states:
1. Be prepared for the worst, just in case.
2. Have your car in good working order - dress appropriately - wear layers & warm socks/shoes.
3. Throw in a couple blankets & some snacks (granola bars good for storage) - keep gastank full.
4. NEVER, NEVER leave car if stalled - highway patrol or wreckers will come looking for stranded motorists on a regular basis during inclement weather. Wind Chill is deceiving & can sap energy & affect your judgement very quickly.
5. If warnings are bad, they close the roads for a good reason - stay off them!! Don't make someone risk their life to come get you. You'll be more comfortable in a motel room than stuck in the ditch in the boring cold.

Let's think positive and hope the warm spell continues!

By the way - roughly, it takes 6 hrs to drive from Minneapolis to Jamestown, ND (1 1/2 between Fargo to Jamestown). Again, 1 1/2 hrs from Jamestown to Bismarck, and about 2 hrs from Bismarck to Dickinson, driving 65 to 70 MPH.
It's wide open country, with nothing to block the wind. Not a problem (just annoyance) unless it comes with snow, which can make visibility restricted at times. Check road conditions if the weather seems "iffy".

Google News this morning "Bus crashes on icy Montana interstate, killing 2 and injuring more than 30". It was going 65 in a 75 mph zone. Road conditions are everything.