I have been watching the cross training here among many other places of Dimitry Klokov. He is a very popular character on the web, and you can get ideas from how he trains and does things. Buy one of his t-shirts for inspiration.
Klokov, being at the end of a legendary career, looks for a big blow every time he trains. You can do all this stuff in a small area and you don't need a lot of fancy equipment. Everything is up tempo. No time to waste walking around trying to figure out how to get out of your work out. Instead, you get right to the cardio. Klokov gets stuck on an exercise and he keeps at it. Instead of that dumbell, substitute a broom handle or crowbar.
One I like is skipping rope, though it took me a long time to get going on it. Some old men are capable of hanging on to basic strength, but endurance goes down the tubes. Another exercise I see Klokov encouraging people to do to build up basic strength for other more complicated and difficult exercises is beat on an old tire with a sledge hammer. Try that and eventually work up to 100 reps. You can easily do that in a small garage space. Then pick up the tire by an edge and flip it over till you get to a good blow. If by some miracle of life you don't have an old truck tire abandoned in the back forty, you can get truck tires at the dump for nothing. I am impressed by this stuff because it gets to the cardio and it is general body. The idea of spending hundreds of dollars on exercise equipment makes no sense to me. Klokov doesn't have any of the exercise machine manufacturers tattooed on his chest. Barbell, dumbbell, kettle-bell and wooden boxes are about it. You can get everything you need at the dump. He says he gets fired up by weights that have some color to them. Put a chain on your big junk tire and tow it around the yard. Just make sure you find a place to work on the abs. And don't forget flexibility exercises. The older you get the more important those abs are. Old folks get really soft in the ab area. And get off your sorry butt, get your legs into motion and drag something around for ten minutes a day. Eventually it might be so much fun that you'll try some of the other stuff, and increase your exercise program to twenty minutes a day plus a twenty minute walk with the dogs. That goes for you ladies, too, who think you must be dead by 70.
I have been running into the stupid old man or stupid old woman syndrome quite often lately, as I am always out and around in the world. Shy and retiring isn't my thing. One of my fellow stupid old men says it is class warfare, it has to do with the grey hairs and the colored hairs, and we must get up our spirit to battle them. Work out every day, fellow stupid old folks, and get up some spirit to take them to task, those youngsters, whom I have noticed acting very stupidly lately. At the very least you'll wake up the wild old cat who is curled up in the shavings on a cold winter day looking like a hockey puck.