The concept of "working out" can have vastly different meanings - depending on who you ask.
If you're a "50 - 60 something" who's just looking to stay active - that should be a reasonably easy goal to attain while traveling. Bicycling and walking are "go to" exercises for most RV'ers to keep the blood flowing. We've found that many parks have group exercise programs such as aerobics and/or water aerobics on the calendar.
If you're looking to up the ante a hair - look for an "exercise" park in the area your staying. You've likely seen the parks with a handful of "exercise stations" spread out along a walking path.
Some parks offer an "gym" (the ones we've seen have usually had a handful of machines (treadmill, stationary bike, elliptical machine ... along with some sort of weight machine). More of the park "gyms" we've seen looked like they were basically an afterthought and rarely used ... but, if you're motivated ... you can probably get something out of that.
Local bicycle shops can usually hook you up with recurring group rides held by local bike clubs.
We like kayaking - and usually have a couple of boats strapped to the top of the toad. If you're anywhere near water - you can work up a pretty good sweat if you put a little effort into it doing that.
If you're staying in an area for any length of time - you might check out local gyms if that sort of workout is your thing. You might check to see if your medical insurance offers any discounts. Our medical insurance is under Michigan Blue Cross / Blue Shield - who offers a program called "Blue365". For $25 a month - you get a "Blue365" card that is good for entry at something like 9,500 gyms across the country. In our area, a "Blue365" membership will get you into national chains like LA Fitness, Anytime Fitness and Curves - along with numerous others. If your the type who will hit the gym - it's not a bad deal, if for any reason, because of it's portability.
Now that we're retired, we've got the one thing that is critical to making most exercise programs successful - TIME! With time on our hands - it's just a case of finding opportunities (and there are tons of them out there!) and choosing how we want to spend it.