Hotel
This is where the wedding will happen! There are guest cottages and hotel style lodge rooms. Check out their website to see some of the fun activities offered by the YMCA. https://www.ymcarockies.org/things-to-do/activities
Travel Note
The YMCA holds its cabins for members until April 1st. They recommend booking a lodge room now and then trying to get a cabin as early as possible on April 1st. There is a 3 minute drive between ceremony and reception, so you will likely have a car to drive to whichever lodging you reserve. The YMCA also has a very detailed map on their website.
Flight
The Denver airport is the closest option. It's about 1.5 to 2 hours from the airport up to the YMCA. This will depend on tine of day for traffic and if you take E-470, which is a toll road. That toll will cost at least $8.