The exercise that works the best for me is walking. Just walking. It may seem too simple but you move all your body. That happens too with swimming but is much boring for me.
So, I don't want to own a car. I try to travel walking as much as I can. So the transport time is fitness time too.
I have changed the speed and duration of daily walking very much with the years.
Now I use to walk an hour each day. Without worrying about a certain speed. Just natural walking or so.
That's like 6-7 kms each day (4-5 miles). So 200 kms every month. (130 miles).
It could seem too much but now I don't even see it as an exercise. If I count the walking I do to go to the places I use to go, all I have to do is add some time more walking around my town and it's done.