Of course there is always running, walking, hiking and biking. Also there are the exercises that do not require any equipment such as push ups, sit ups calisthenics etc. These are all great ways to stay in shape, but some of us need a little more.
I used to carry two 25 lb. dumbbells. This proved to be cumbersome and added unnecessary weight to the RV. We have come up with several lightweight items to carry on the motorhome that don't add any weight and take up very little room.
Resistance tubes (or bands), Pilate bands, and a yoga mat have served us very well. We use resistance bands from Black Mountain Products purchased through Amazon for $35. The set came with a variety of accessories and several bands of different degrees of resistance. Our yoga mat and Pilate bands were purchased, very inexpensively at Wal-mart.
These items, along with some You Tube videos have greatly enhanced our workout routine.