River Run Resort in Granby offers over 400 RV regular and waterfront sites with electric and water. It has a lodge, cabins, and glamping with an Airstream park and Conestoga Wagons. There's a fitness center with yoga, massage, and spa services. The swimming pool is large and has three hot tubs and The Tiny Tap offering poolside cocktails. There's a large off-leash dog park near the resort entrance and a smaller one at the RV sites. You are about 20 minutes from Rocky Mountain National Park entrance.
If you go:
They're open year round; however, the winter RV sites are dry camping only. Rates and amenities available vary by season.
Links:

1051 Summit Trail
Gramby, Colorado 80446 USA
riverrun@suncommunities.com
Phone Numbers:
River Run Resort
+1 (970) 557-0200
+1 (970) 557-0200