One way retired RV'ers might consider helping is to volunteer for a week at Sager Brown, which is the UMCOR (United Methodist Committee on Relief) depot in Louisiana. Volunteers assemble health kits, school kits, and so on, to go to relief efforts. Sager Brown has dorms for volunteers, who do pay their own expenses- which are modest, about $100 for the dorm for a week and $85 for food, but also has 12 RV spaces with hookups ($20 per night.)
My mother has been down there a number of times and always enjoyed it.
I imagine other volunteer opportunities of this sort exist, this just happens to be the one I know about.