First, look at the link Thom gave you to another very similar thread running right now.
A few comments:
Your first two days are probably more like 10+ hours of driving each day. It's really hard to average even 60 MPH for such long distances. Fuel breaks, bathroom breaks, food breaks all take time out of your trip. Breakfast, breaking camp in the morning and then checking in and setting up at your destination and you're looking at more than 12 hours every day. It's doable, esp. going across states like KS, MO etc., but draining. Once you get to the mountains, your average speed will drop even more. As Busskipper noted, if you can get a couple of hundred miles under you belt the evening before the "Day 1" on you itinerary, that will help with your scheduling the rest of the way out. Maybe something around Springfield IL or Davenport IA, depending on which route you use?
To look for campgrounds along your different routes, I'd check out
this map. Zoom to various areas to see public and private CG's.
If you don't want to see the same sights on your trip out and back, go one way on I-80/I-76/US 285/US 160 and the other direction via I-70/US 40/CO 96/I-25/US 160.
I would skip Colorado Springs as a stop over. You'll be going by so much better scenery IMHO. Plus if you're going to be here in the summer, head to higher elevations where it's cooler. Over all the guests who have visited us over all the decades, Colorado Springs has never been a place I have taken any of them.
I'd make Durango your home base in SW Colorado. Ouray is nice, but there's more variety of landscapes if you're in Durango. Besides, taking the train if you're staying in Ouray just isn't practical. That's a minimum of two hours driving each way just to get to the train station. And traffic is often slower as there are lots of people looking at the scenery.
The train is a must do IMHO. We're not big on "touristy" attractions, but the train is something we've done several times and will do again. Get the book Cinders and Smoke by Doris B Osterwald before you go on the train. It has mile by mile descriptions of things you might not notice otherwise.
You'll need a full day to do Mesa Verde. Get to the visitors center early (8:00 a.m.) to secure tickets to one or more of the guided hikes. With only one day, I'd stick to the ruins on the Chapin Mesa road as it's a fair drive out to ruins on the Wetherill Mesa Road. Besides, there's lot to see on the Chapin Mesa road from turnouts along the road with minimal hiking.
To visit Ouray, take a long day trip up to Telluride, then over to Ouray, where you can take a couple of hours at the Hot Springs Pool. Best views from a pool anywhere! Then back through Silverton and on to Durango.
As I noted, check out the other post for more ideas.