Colorado?

You will want to narrow it down for us a little. Big state - lots of different environs. Rocky Mountain National Park should be on everybody's life list. Silverton and Durango - very cool (cowboys and silver mines). We stopped at Sylvan Lake state park just south of the national park and found a real gem.
It helps to know your time frame and what you like to do. Also any "must haves".

X2 on a Big State. Colorado Springs area has lots to see and do also.

Hey, it is a big state - where are you going to be? Anyway, some of my favorites - Mesa Verde National Park, Leadville, particularly for the month of August; lots going on including a pair of 100 mile bike & running races and camping around Turquoise Lake, Hiking to Hanging Lake near Glenwood Springs, Great Sand Dunes National Park, and Rocky Mountain National Park.

Added a link to my visit to Leadville in August, 2012.

Durango/Silverton
Wolf Creek Pass
Great Sand Dunes
Leadville
Canon City/Royal Gorge
Estes Park (the drive between Granby and Estes)
The Coors Brewery in Golden

Lots to see and do in Colorado. We have a daughter living out there so we are out there a couple of times a year and just barely touched the surface. We did work camp at the KOA in Buena Vists for a summer and really enjoyed it. Nice folks who run it and there is lots to do in the area, hiking, rafting, climbing, horseback riding, hot springs, trout fishing. Lots of national forest too if you like to boondock. Leadville is just north of there, Fairplay just east, and Salida just south. We also liked RMNP and that area, Durango/Silverton is gorgeous with the added attraction of the Durango/Silverton Railroad, and Mesa Verde NP.
If you narrow down your choices we may be able to provide more detailed information.

We enjoy staying near Ridgeway State Park (Black Canyon of the Gunnison National Park), Ouray KOA campground and outside Durango, CO. We were motorcycle camping that trip.

The state has a lot to see and do.

As a suggestion, when asking questions like this, provide a little more information like kids and ages, interests, type of camping (state parks vs, resorts), ect. You will receive much better information.

Sorry about being so vague, I was in a hurry. I am debating changing my summer vacation plans. Last year we spent two months touring the West. This years original plans were to head out to Maine and cruise down the coast a little bit. I am having trouble getting excited about that trip after being spoiled with seeing the West and also knowing that we missed the entire state of Colorado. I will have about 3-4 weeks to spend in Colorado during the month of July. I will definitely be going to Rocky Mtn NP. Any other ideas or suggestions will be greatly appreciated.

Oh yeah and BTW, we have two daughters (11 & 14). We enjoy hiking, biking, and pretty much anything outdoorsy. We usually shoot for State Campgrounds first, then go private. My girls really enjoy all the Ranger programs that State Parks provide, always a lot of stuff to do.

Thank you for providing more info; it helps us help you.

Lived in Estes Park 8 years and have traveled the state for that 8 plus 10 more - all I can say is that there is so much to do and see. We will be back there this late summer / fall for the colors.

State Park great places include Cheyenne Mtn in CO Springs sand Ridgeway in Ridgway.

Rocky Mtn NP is a must and Thunder Mountain (who lived there far longer than I) and I could write you a book on that area. And there are other very good people on this Forum who have lived in the area or been there many times who will help you along with this.

DW, DD and I also love the southwestern part of the state and will be there again this year - Buena Vista, Leadville, Montrose, Ouray, etc. We also are outdoors types and avoid cities as such.

Email or PM me if you would like.

Lauren

Pretty much anything west of I-25!