I, too, am 61 and while DH and I still live in our home, he had a medical situation last Jan/Feb which had him in a nursing facility for 8 weeks. I was home alone with our big house in the middle of the winter. First thing I did was buy a snowblower I can handle. I got a small electric one, good for up to 6" of snow. It didn't do me much good during the storm where we had almost 5 feet of snow, but it sure was valuable for overnight snowfall, keeping the driveway, walkway, and path to the oil tank cleared. The important part to me was that I could move it in and out of the house, start it, and operate it without hurting myself. I also did little things like moved the trash barrels to the front porch so I didn't have to carry them as far, and moved the recycling containers from the basement to a room we rarely use, so I wasn't hauling bins up and down stairs. I was lucky when we had two Big Snows in that one of my neighbors came over with his huge snowblower and cleared about 90% of my driveway for me! However, we had some storms where I didn't want to bother the neighbors but that were too "big" for my snowblower, so I found a teenage boy to help out. He shoveled about half of the driveway (8" of snow) and all of my deck for $20. The deck had 3 feet of snow on it! This past summer (as DH's leg wasn't up to it), I did what I could with the front yard and hired out mowing the backyard to the same boy who did the shoveling last winter. It was worth the $10 to have someone help with mowing (our lot is 3/10 of an acre, so not very big) so I didn't wear myself out. Fortunately, DD and her boyfriend knew DH's recovery was slow and challenging, so they came up for a week-long visit and spent the time doing all the house things that I couldn't do on my own.
For me, it was key to keep things handy and manageable. No, it's not common to keep a snowblower and recycling bins in the front living room, but we don't use the room and that's what was convenient for me. I also got in the habit of stopping at the market every couple of days to get things I'd need, rather than doing a big shopping and have to lug all those groceries up 10 steps into the kitchen. I was going by the store anyhow, and although it took more time to stop every few days, it was easier in the long run. Maybe you can focus on things that need to be done and then how to make them easier/more convenient on you? Nobody is keeping a score card as to how you do things or how well you do them- you need to do what you can, however you can! Good luck...
Oh hey, I just thought. Would you consider a roommate? We have had grad students live with us at different times, when we've had the financial need and space in the house. Also, I have a friend who found a roommate for her mom. Not sure how she found or vetted him, but he pays a reduced rent in exchange for taking care of the house-stuff (yard work, small repairs, shoveling, etc.). Might be something to keep in mind.