Have documentation on your person(s), in your car and also a sign on your RV door that there's a pet inside. This would also be helpful if there was an RV fire. When you sign in at a RV park, let them know. If taken by ambulance from your RV or car they'll see that there's a pet and it will be taken care of. They won't leave it behind uncared for. Things have a way of working out. Don't get yourself worked up about this. Pets will adapt to their different circumstances even though you think they may not. Think of all the shelters and the pets that had homes previously. They're now adapting, not having separation issues. When adopted they become one of a family again.
Since we were full-timers and traveled constantly we always carried an updated travel route/information form in our car and on the dash of the RV. It stated our personal info, who to contact in case of emergency (& this person should know about your pet), where our RV is parked & where we plan to stay next, license plate numbers and description and a tentative route we'll be taking. Of course, things/routes/campgrounds can change but this would be a start in finding our RV. This could also be helpful if one of you is in town shopping or whatever and you would be in an accident. Then the emergency folks would have a way of finding the other half of you. We never had to use it but it's just another thing you can do. You can't cover every incident. Be positive!