Hi Ray, I faced this issue when cancer restricted my wife's mobility. On a trip to Hawaii, we found a rental company that had a small powered scooter waiting for us at our hotel. That worked fairly well, as we were in Honolulu and the buses were all equipped for accessibility.
On a trip to France, we rented a travel chair in the US and checked it at the airport. I provided the power on that trip. This was less than Ideal, as the travel chairs tend to have small tires - great for the smooth hallways of the Louvre, but tough on gravel walkways at the Versaille Palace. We did find that the French were extremely accommodating; pushing us to the front of the line at passport control, free entry to museums for both my wife and myself, and so on.
If your powered chair has the FAA-approved gel-type batteries, it can also be checked on the flight. Your airline and chair/rollator mfg could tell you more about that.
The main issue will be where do you want to go? Our experience traveling in the old towns in Europe and in parts of South America is that many places are just not setup for mobility issues. For example, aggregate sites like Expedia, Booking, etc. have filters you can use to search for only accomodations that are wheelchair accessible. I just did a search for hotels in Lisbon, Portugal and once I applied the filter, it did find some nice hotels, but it also eliminated 97% of the ones available in my time frame.
So to sum up, a lot depends on your particular needs and choice of destinations, but travel with power chairs or rollators can be dome but definitely requires careful advance planning and research.
Hope that helps, and let me know if you have any other questions.