I would recommend driving from MN through SD. Visit Rushmore and the Black Hills. Drive through WY, visiting Yellowstone, the Grand Tetons, and Jackson Hole. Continue through UT and on to AZ. Come back through Flagstaff, and NM. Come up through the Rockies, seeing Estes National Park. Then come through Denver, and across the plains-NB & IA. Then return to MN.

There are a lot of places to camp and see on this routing.

Have fun!
Jason

Thanks! We are wondering about there being snow crossing the Rockies in April? Would like to keep more southerly- Went to Black hills, Badlands, Rocky Mountain on a previous trip (wonderful!)

Fortunately, it has been a mild winter this year. That being sais, there are a lot of web sites that monitor road conditions in the Rockies.

Sounds liek a great trip!

Jason

You'll be traveling through the west in April with a small camper. That being the case, you'll have a LOT of flexibility on where to stop, as I seriously doubt you'll find a campground that's full. The FAR bigger problem will be finding one that is OPEN in April. In Yellowstone, for example, only one campground is open prior to May 10th.
www.nps.gov/yell/planyourvisit/camping-in-yellowstone.htm
and a lot of facilities won't be open there
www.nps.gov/yell/planyourvisit/open_closedates.htm#april

Because of this flexibility, you'll be able to take just about route you want, even at the last minute, in order to miss bad weather. My suggestion is thus-
- get to Omaha
- drive I-80 through Nebraska, and I-76 to Denver. If fascinated by western history, detour to Scotts Bluff NM.
- if the weather is okay, visit Rocky Mountain NP and/or take I-70 through the Rockies.
- if the weather is NOT okay, then continue south on I-25. We'll assume that you hit good weather.
- after entering Utah on I-70, head south on US-191 to Moab. Visit Arches and Canyonlands.
- continue south on US-191 to Monument Valley. Watch your gas gauge in Utah and Arizona; stations may be hard find!
- then head west on US-160 towards Tuba City.
- head south on US-89, and then west on AZ-64 into Grand Canyon. Use
www.recreation.gov/camping/Mather_Campground/r/campgroundDetails.do?contractCode=NRSO&parkId=70971&topTabIndex=Search
to make reservations for a camp site when you know you exactly what date you will be arriving.
- after The Canyon, you can head go south towards Flagstaff and then east on I-40, visiting Petrified Forest NP.

If you detoured to avoid bad weather, head north on US-491 to get to Moab. Then return via I-70 to Denver.

If you've already been there, continue east on I-40 to the Albuquerque / Santa Fe area.

After this, you'll just have to return via the Plains. What route you take depends on whether there is any city between where you are, and home, that interests you.

End of April or beginning of April for the start of your trip?

Do you want to go as far south as I-40?
If so, you could come down thru St. Louis area, then on to Memphis. Arkansas has some awesome spots in April. The Upper Buffalo River is normally very good(although we need some rain at this point-but I expect it will be fine by April, but nothing is guaranteed). The waterfalls that area are very good. Plenty of campspots and many other good Arkansas State Parks.
Then, the drive through Oklahoma and Texas will be very boring on I-40. After The GC, I would do a lot in Utah-Page/Lake Powell, Zion, Bryce, Capitol Reef, Arches, Goblin Valley. Great campgrounds at Goblin Valley and Capitol Reef, btw.
Then go back through Colorado. Since you have been to Rockies, perhaps consider stopping at Great Sand Dunes(best around the end of May-when Medano Creek is flowing).

Durango and Mesa Verde would be a thought too.

Yellowstone is a no go, almost everything is closed. Totally pointless in April unless you have a burning desire to see it that time of year - which you don't based on your posts.

April is a great time to visit the southwest.

With a month, I would head south immediately and hit Colorado on your return trip. You have time to go all the way to Big Bend National Park in west Texas - it is out of the way but you have a month so that's not a big deal. One of the biggest, least visited parks in the lower 48 and April is perfect there. From there, head west to the Grand Canyon. Possible stops are Carlsbad Caverns, White Sands, Saguaro (Tucson), Organ Pipe (southwest of Tucson) and then up to the Grand Canyon.

After the Grand Canyon, hit the parks in Utah and then probably go to southwest Colorado or northwest New Mexico, then head home.

If you actually do visit Big Bend, and aren't interested in the stuff around Tucson/Phoenix, you could head north after El Paso and get to the Grand Canyon via northwest NM/southwest CO. I don't think that route makes much sense unless for some reason you want to drive straight home after Moab.

So my rough itinerary would look like this:
Day 1-4: travel to Big Bend. You could go via I35 with some detours for sightseeing along the way (Kansas City, Oklahoma City, the prairie in Kansas may be full of wildflowers at that time). OR you could drive along the Mississippi River to Memphis, then cut over to Dallas and Big Bend. That route might be more scenic but would take longer.
Day 5-7: explore Big Bend
Day 8-10: travel to Grand Canyon
Day 11-12: Grand Canyon
Day 13-24: Utah
Day 25-30: Colorado and drive home

That's a lot of time in Utah but you can easily fill it up and then some. 6 days for Colorado plus the drive home might actually be too much because of snow at high elevations, so you'll be somewhat limited in your activities in Colorado. It really does matter somewhat on whether you are leaving early April or late April, because several weeks will allow for a lot more snow to melt up in the mountains and that would open up some more hiking trails, etc. No matter what though, May is good for waterfalls and lower elevation trails in Colorado.

Like I said, that's a rough itinerary, your actual route and days allotted will vary depending on what piques your interest. Spiro would have a lot better suggestions for Missouri, Arkansas and Oklahoma than I would so I'm not even going to try to give you any ideas for those areas.