Here's what Boulder OSMP has to say about Halfway House: 

Constructed by the Civilian Conservation Corps in 1933-34, the Amphitheater is a rustic outdoor facility made from local stone. It features a large circular area, a small stage, tiered stone amphitheater seating, and magnificent views. The Sunrise Amphitheater is located at the east end of the Flagstaff summit area beneath the large flagpole.

Sunrise Amphitheater is located at the top of Flagstaff Road in Boulder. Here is a Google map pin that will take you to the parking area. 

You are required to reserve Sunrise Amphitheater for ceremonies. Here is more information on reserving the site.

Pets are permitted at Sunrise Amphitheater but must be on a leash unless they are participants of the Voice and Sight Control Program.

Sunrise Amphitheater is closed seasonally from Oct. 31 - April 30 . You can expect similar weather at Halfway House as Boulder. 

Sunrise Amphitheater is easily accessible with a short walk from the parking lot. The main amphitheater is wheelchair accessible via a short trail from the parking area.

There is a parking area at Sunrise Amphitheater. You may consider hiring transportation depending on your guest count.