Toronado,
I'm glad to hear you'll be visiting my neck of the woods! I think Rocky Mountain National Park is a must see. Estes Park is the town at the base of the park. It's about 90 minutes northwest of Denver. Estes is touristy with lots of things to do and see, like the Stanley hotel that Stephen King's book The Shining is based on. Rocky Mountain National Park is big, would probably take the better part of a day to drive. Granby is not far as well and is a beautiful area. How long will you be in the area?
Something to consider is giving yourselves a few days to adjust to the altitude before trying hiking as some people do get altitude sickness. Also in May, it may be 70 degrees when you head out from Estes and it'll snow when you reach the higher peaks in Rocky Mountain National Park. You'll head out in shorts and t-shirts and end up in a parka 2 hours later. All part of the charm!

Vail, Breckenridge and Aspen are ski resort towns that switch over to hiking, camping, fishing and horseback riding in the summer and are in the general vicinity you're looking at.

The Colorado Springs area is great, too. I'll see what I can find out about railroads in the mountains.

You're going to love your visit here!

Barb

I went to Colorado back in September... see link for pictures...

Here is a link that might be useful: September 2011 Colorado Trip

you might want to visit the conifer forum.. and look into some of sluices posts.. which are falling down a few pages by now ...

check out the link below

ken

or this one:

http://forums.gardenweb.com/forums/load/conif/msg1211141019827.html?3

Here is a link that might be useful: link

The two cool old time train rides I'm familiar with are quite a ways from Denver - but you can bookmark them for when the kid(s) grow up.

Going from memory on spelling/geography...

The Durango-Silverton line is in the southwest part of CO, and connects you with CO mining history in the mountains there.

The Combres Toltec (sp.?) line actually straddles the Colorado-New Mexico border in the southern-southeast part of the state.

Thanks guys. I am really starting to look forward to this now.

Barb, we are planning on spending a week in Colorado late spring/early summer. Sounds like the first Day or two I should do the wife's stuff. Antique shopping is usually less strenuous than hiking!

I'm going to go through them posts on the Conifer Forum too and see how close I can get to some of them rail lines.

Plant-related activities you might find interesting (and different from what you find in the Midwest):

M. Walter Pesman Alpine Nature Trail on Mt. Goliath, near Mt. Evans, approx 60 miles west of Denver: Rocky Mtn. bristlecone pines and other very hardy plants. This unit is run by the Denver Botanic Gardens. High elevation, will be cold. Must check to see if Mt. Evans road is open.

The xeric units of the Denver Botanic Gardens (Water Smart Garden, Dryland Mesa, etc.). The rest of the gardens will also be nice at that time of year but not all that different from MOBOT and others.

Florissant Fossil Beds National Monument about 20 miles west of Colorado Springs: huge trees and other plants and animals from 35 million years ago, excavated from volcanic ash.

Be prepared, depending on where you go, to see some large areas of beetle-killed pine and burn areas from 2002 (SSW of Denver).

There are a number of good books about the "ghost railroads" of the Colorado Rockies that will give you the history and maps of various now-abandoned rail lines.

A week will go by fast, plan to return.

For a couple of rail options close to Denver, you could look into the Georgetown loop railroad, or the Pike's Peak cog railway. There's also a railroad museum in Golden. Have fun in the Centennial state!