First time to CO - where to go after Denver?

Just 8 miles from Golden is Red Rocks Park and Amphitheater:
https://www.redrocksonline.com/explore-red-rocks/

After you've scrambled around the park, you can also visit the Red Rocks Hall of Fame of the artists who have performed there:
https://www.redrocksonline.com/explore-red-rocks/red-rocks-hall-of-fame/

The website mentions some works projects that are scheduled to end in April, but worth checking to confirm they've fully reopened before your visit.

Further from Golden (130 miles) is the Royal Gorge Park:
https://royalgorgebridge.com/

You can choose your thrill level from the gondola, a zip line, and the Royal Rush Skycoaster.

Check out Estes Park, north of Denver. From there is an entrance to Rocky Mountain National Park. Beautiful scenery and wildlife. (Do not approach the Deer, Elk or Moose! or bears!)
Sometimes the elk and deer and even bears wander around the town. The famous Stanley Hotel is there (Famous from the movie The Shining) The Hotel is supposed to be haunted, they do offer tours. Quaint little town.

Have a great trip! Welcome to Colorado!

Mimi

Not too far from Golden is Estes Park/Rocky Mountain National Park. Although a bit farther is Aspen. Both offer great views with many hiking possibilities.
RDJ

I think Aspen is a lot farther than Estes Park. Rocky Mtn National Park can be driven through and or do some hiking. Some trails easier than others. If you take Trail Ridge Road to the top, there is a lookout and maybe spot some mountain goats. If you go all the way over that's where the Moose usually are. And don't be fooled, all of these big animals are fast!

If you do decide to hike make sure to drink a lot of water. I don't know where you're coming from, but some people take a while to get used to the altitude. We have had visitors here that it really bothers and some that it doesn't. So I would suggest easy hikes, taking it slow.

A little ways West of Denver is Idaho Springs. Cute little town got it's start with the gold mining. There are still a couple of Gold mines there, one there is a very large touristy tour. Our favorite to take visitors to is the Phoenix Mine. We discovered it with our young boys in 1991 when we first moved to Colorado. They loved it and so have our out of state visitors. ( Our youngest son wanted a gold pan for Xmas one year because he liked it so much). On the way home from the Phoenix Mine we always had to stop at Beau Jo's Pizza in Idaho Springs.

Come back with any other questions, we have a lot of Colorado people here on the Forum.

I hope you enjoy Colorado,
Mimi

Pike's Peak and the Air Force Academy are within 100 miles of Denver and near each other.

Are you looking for day trips to occupy your extra time or a destination to go for the 2-3 days?

As you have asthma be sure to take time to get used the thin air. Might take awhile so be cognizant of your pace.

https://www.redrocksonline.com/

See if you’ll be there during the Red Rock season.

Estes Park, Rocky Mtn. N. P. ( check to see if you need to make reservation to get into the park)
If you are interested in Lions, tigers, bears, then check out the Wild Animal Sanctuary in Keenesburg, a little NE of Denver

Keith,

I totally missed the part about asthma, so the altitude could be a problem with hiking.

The recommendation to the Wild Animal Sanctuary is a good one! The animals are not caged. You walk on elevated walkways to observe them, not like in a zoo. They have taken in many rescued animals. It is an easy drive from downtown Denver.

A very pleasant excursion from Denver that wouldn't require renting a car would be to take the scenic train ride to Glenwood Springs and spending a couple of days there. It's a pretty little place - one of our favorite destinations in Colorado in fact
Can Google it to see if it might be of interest.

Edited to add: Glenwood is at about the same altitude as Golden (and Denver) so once acclimated you'd probably have a little less huffing and puffing than at Pikes Peak or RMNP. Though either would be great the altitude might be pushing it if you're concerned about your asthma kicking up.

First, you really will be better off renting a car - it makes it much easier to get around. There are buses but cars make it a lot easier. Just keep in mind that the area you are visiting gets VERY crowded, so take that into account when driving. On Fridays afternoon, everyone from Denver heads up into the mountains, and on Sundays, they all come back. So I-70 is jammed with traffic. You can pay more to get in the faster priority lane or you can just try and avoid those times. There is a back canyon road that I always take - lots of people don't know about it and it's a much prettier drive than I-70.

There are lots of towns on the outskirts that are fun to visit. Golden itself is worth checking out while you're there. I second Mimi's rec for Idaho Springs - that was always a hit with visitors. Make sure you stop at Beau Jo's for pizza. I used to take people there all the time when I lived in Evergreen. And Evergreen is a nice stop as well - beautiful lake and there are some hiking trails and back country roads to visit. If you go down a back road past the lake, you will drive past Willie Nelson's old place (that he lost to the IRS). :)

Another interesting place is Central City, which is a bit farther past Idaho Springs. Lots of history there, with old mines you can visit, and their main attraction, the historic Central City Opera House. There is also the Face on the Barroom Floor (a painting on the floor) at Teller House Bar, which is fun to see.

There's also the buffalo overlook at Genesee (the first exit after you get into the mountains heading west). You can pull off onto the overlook and look for the bison that are sometimes there. https://www.uncovercolorado.com/wildlife/buffalo-herd-nature-preserve/

And Georgetown is also an interesting place to visit. It has a preserved main street with older buildings that sit in a beautiful setting in the mountains. I used to love to go there and visitors always enjoyed it.

Head west into the ski country. All the resorts from Breckenridge to Vail have summer activities as well and the towns are busy with tourists. I'm not sure about activities at Winter Park (north of Denver) but there was a train you could take there from Denver.