All of your scenarios are possible. But its also possible that the owner had a 100 mile highway commute to work each day plus personal miles. You could go on and on. If it has been properly serviced and the condition is commensurate with the price then I would say green light. Unfortunately there is some question now about a possible collision so that would also need to be researched.Here in Atlanta you see limos competing with taxis at the airport so they sit in a big parking lot waiting to get the the front of the line. It is easy to roll up the miles doing that. Another possibility is that it was used as an Uber black. I worked for a courier company years ago. Our local trucks averaged 10,000 miles a month. High idle time is increased engine wear. That is taxi cab level mileage