The wife and I also work out regularly. All of the above are good ideas, but the key to any exercise program is consistency. Since we travel far and wide, the only answer was to have our workout stuff with us. For me I carry a set of Bowflex adjustable dumbbells and a flat bench that folds up flat. Medical experts agree that cardio is important as we age, but so is doing weight bearing exercises to maintain bone density. I have a regular routine that encompases about 10 different lifts. Not overly heavy, just varied. Kind of like the "Curves" workout system.
I also need to maintain flexibility and do core work (IE situps) so an inflatable exercise ball is the hot ticket. It can also double as an extra outside chair or foot stool when we are just hanging out. The DW has some lighter weights, but likes additional activity in her workouts, so she has found a particular female workout instructor that makes workout DVD's. She can do the routine while playing DVD on the rig's TV system, or on her laptop.
We usually do weight workouts one day, then cardio the next. For variety we may jog together, brisk walk, or ride the folding bikes. I used to have regular bikes, but riding them all over the country while strapped on the back of the Jeep pretty much kills them in a few years. The folding ones ride in the back of the Jeep and are still like new every time they are used. Then also don't forget to mix in off days to give your body a chance to recover.
This is just our system, and you can see they vary widely. The important thing is whatever you do, just do it regularly.
