Hi there! We are planning to be in Frisco early June for 6 days. Our children range from 10 months to 9 years. I'd love suggestions for easy day trips and suggestions in general. We love nature, exploring, and wildlife.My husband and I have travelled to Denver/Boulder/Colorado Springs before children, but could certainly use some ideas for showing CO off to them!

You can do gold mine tours in Breckenridge. Breckenridge has a nice recreational center - indoor pool, etc. There is an Alpine slide in Breckenridge. In Georgetown you have the Georgetown Loop railroad - narrow gauge railroad with a really interesting silver mine tour.

There is the 12 mile, paved, loop, Mineral Belt trail in Leadville. A real unknown gem.

The huge, outdoor hot springs pool in Glenwood Springs along with a chair lift. All of the ski areas have a number of kids oriented activities especially at Vail.

There is lots to do.

The elevation in Frisco is a little over 9000'. Even if your kids don't get altitude sickness you might.
Plan on 3 days in Glenwood Springs or Aspen before coming back to Frisco.
The kids should love the hot spring fed swimming pool and Glenwood Cavern which is at the top of a gondola ride.
http://www.colorado.com/cities-and-t...enwood-springs
Glenwood Springs is a little below 6000'. The canyon east of town is spectacular.

Thank you very much for the input! I had wondered if staying at a lower altitude for a night or two before heading to Frisco might be advisable. Would spending a day at RMNP be doable from Frisco in your opinions? If so, what would you recommend?

The western entrance of RMNP is not far from Frisco and should be a pleasant day.
Don't over worry about altitude but DO and especially with the kids, drink more water than you ever have before, all day, every day. Everyone carry a water bottle.
Frisco is a super cute little town. Breckenridge has a lot of stuff to do also with a big rec center.

Oh, and don't forget the sunscreen!!

Don't know what elevation you are coming from but acclamation is slow - about a 1000 feet per day. So if coming from sea level it will take most of your six days just to get to the Denver level. But the concern about altitude sickness is often over stated. It can be a problem especially if you have some existing breathing problems. If you don't and everyone is generally health you should be OK - just take it easy and drink a reasonable amount of water on a regular basis. You need to increase your red corpuscles by about 20% since you lungs are not as efficient at higher elevations.

You could do a day trip to RMNP from Frisco as the western entrance to the park is about an hour. If you go complete through the park on Trail Ridge Road and end in Estes Park you will now be 2, 2.5 hours back to Frisco. So it could be long day for the youngest.