We stayed here a few August's ago and it was good, full hookups. 11km West of Drumheller on North Dinosaur Trail.
www.htr.ca then you can find the Drumheller rv park, I wasn't finding it on Google maps for some reason.
If you have a chance while in the area, I'd highly recommend Dinosaur Provincial Park. It's about 1 hr 50 mins SE of Drumheller, but has the most amazing terrain. Some of the sites have power, no full hookups but there is a sani dump on site.
We had a lot of aggresive wasps and many mosquitoes when there near the end of August, so be prepared! Enjoy, it really is an amazing place!