Welcome to the forum. Always like to hear from that side of the ocean. jmurray from Scotland is a very good member and we hear a lot from him. The 0 turn mowers are getting popular in this country. Maybe you should look into one of them in a smaller size? Don't know what you want to spend on a rider. You say you heat with wood. What do you do as far getting fire wood. Cut down trees, cut into chunks and then split. I am also in my 70's and have been cutting my own fire wood for years. The problem is my body just won't take it anymore so I am to the point of buying my wood all cut and split. One of my chain saws is about 45 years that i still use at times but find my new Husky will cut a lot more wood with a lot less work. Collecting old chain saws sound like a fun hobby. I just started collecting old out board boat motors myself.
My neighbour has some 80 acres of mainly Oak, Silver Birch, Sweet Chesnut, Mountain Ash, which he coppices & sells for wood burning, cut to 50cm lengths & split. I help him cut & haul, & I take wood instead of cash in return for my labours ,so sourcing timber is no problem. As you say though the body rebels sometimes & doesn`t want to be put on, this is the reason for wanting a ride on mower as Iv`e got to the stage of not wanting to plod around behind a mower for up to a couple of hours which is what it seemed to be taking to mow & strim my plot The wood cutting is not a problem as I can do it as & when & the timber stands stacked for at least 3years so it`s an on going project, the mowing is more of a must do though otherwise it gets out of hand