I find it strange that older people think they wish to 'escape to the country', at the time of their lives when they are more likely to need the facilities that only towns can offer. My Bil and SiL did this in their late sixties, seven years back, gorgeous house - they both hate it, my SiL still calls her old area in London 'home'. They are now trying, desperately, to move back - very much more difficult.
As you get older you need to ensure that anywhere you live, has easy access to different sorts of public transport, close to shops, GP surgeries, dentists, hosptials, etc. etc.
Find out if any area you are considering has things like good U3A's, WI, etc. to help you to meet, and be part of, different interest groups.
Really find out about any area you are considering moving to - visit at different times of the year and different times of the week, etc.
I made (for me) an enormous move out of London - where I had always lived - to Weston super Mare, when I was in my late 70's. BUT....it was a town I had visted (as had daughter and her family there), for the preceding twenty years. For me it has been a highly successful move, as everything is so very close - all within easy trundling - on my mobility scooter- distance.
Do remember, that friends will obviously promise to visit you regularly - and mean it when they say it - but in actuality may come once or twice and then that is likely to stop or, be at the most once a year. Good to keep in touch with them, but you need opportunities to make new friends in any new living area.
As had been said, a goodly list with all the pros and cons, and lots of time spent investigating any new area,
Good Luck