You may want to contact Andy at Can Am RV in Canada (posts here or writes/advertises in Blue Beret or Airstream Life magazines..) or other RV dealers.. Pretty sure the 31' has high hitch weight (more than 500#) and will need weight distributing hitch. In addition, short wheelbase of G500 means you'd also be urged to be sure you have working anti-sway system.. Beyond that, issues for G500 include cooling and transmission cooling, plus brake controller and wiring for lights, which are pretty easily solved. Andy has set up Chevy Traverse's and Ford Edge's to tow 30' and longer Airstreams, so it certainly is possible, but it is also quite possible to do it wrong and make a mess going over Rockies...
In Theory, there's no difference between Theory and Practice, but in Practice, there is usually a difference...