U.S. 212 from Crow Agency to Spearfish S.D.

IMHO 212 is the only way to go. I found it really interesting, especially compared to the boring interstate.

I had a great chat with a Native American flagger at a stop for road construction. Super sense of humor.

Topped off by a B52 on a low level training run near the Powder River area. Cool!!

I'll agree with most; it's a good road and will save you some time. I-90 is a little more scenic, a bit safer, and has more services should you want or need them. You won't experience traffic congestion on either!

I've driven it and desolate, yes, but interesting. I have driven across this nation and I have yet to find a section of the country that I don't find interesting in some way.

When driving through the Tribal lands I look at the incredible poverty and starkness of the land. Saying that drive it, it's good road and something you may not witness in the future.

US 212 is a good road, will save you lots of time, and you will get to see antelope and/or deer also. Watch your speed through tribal lands, no 75 mph stuff or you'll be in trouble. The drive is relaxing and stop in Broadus for a bite to eat if you wish.

We've driven it many times, no problems, good road conditions.

My 2 cents is no, don't go that way. As others said it's a good 2 lane road. However, there is nothing, repeat nothing out there. We traveled it once and that was enough, no scenery, no cel service. It's got a lot of small ups & downs. We like to travel the 2 lanes across this country but that one is one we won't go on again. Your wife won't like it either.

If you take it at night, be especially watchful for deer this time of year...it is known as "deer ally" in some quarters. It is much more peaceful to drive than the freeway.

It's a good two lane road. Have driven it many times. It goes through some pretty desolate country, it's not sightseeing heaven. Much of the trip you will not have cell coverage. Be aware the vast majority of the time you will be on the Crow Indian Reservation. You won't have any problems, but the people on that reservation will never win any hospitality awards.
And don't forget the first week in August is the Sturgis Motorcycle rally. It's the 75th anniversary and they are expecting huge crowds, possibly near 1 million. Unless it is something you want to be involved with, give the area a wide berth that week and the weeks on either side.

The only reason your routing program recommends it is because it is shorter. It may also be faster, but that depends on the speed estimates. The router knows nothing, or next to nothing, about whether it is better.

Time wise it is only a hour difference (more or less). That's nothing to loose sleep over. I90 follows the Big Horn Mtns south (stays flat), passes a couple of towns, and has a town or two on the east bound leg. 212 is, overall, more remote.

Thanks. I have a wife who sometimes doesn't want to get off of the freeway, so I kinda have to be careful!