You'll probably want to stay at Wapiti or Whistlers campground just south of Jasper. They do have some serviced sites although the unserviced are much nicer sites. It's a good place to park and then do day trips to see the sights. I prefer Wapati.
You can reserve online using the parks canada reservation service.
2017 F350 Platinum DRW
2013 Adventurer 89RB