I am the woman that goes motorhoming alone. My husband is still working, by the way we were neighbors to you before we moved back to Indiana. Still trying to sell our house outside the Woodlands.
Hubby travels and works overseas so traveling is not what he wants to do when home, he wants to be home, don't blame him a bit. We are 67 and 68 respectively. We have a mildly mentally challenged daughter and she and I love to travel. We are now on our 3rd motorhome, its actually the oldest one, a big old 92 American Eagle. Hubby keeps it humming and once or twice a year DD and I take off. We will go this winter for a month or two. If she really doesn't mind perhaps you could go alone. Somehow I think its more then that.
I know I didn't like not having a w/d, hated the Laundromats and for me no TT. I can't hook and unhook and set it up. do you have pets you have to take or leave behind, that could be an issue. I'm thinking you have grandkids she may not want to leave. I would as others said try to work it out or find something else to do together.
I know my husband and I are different, he may go with us after retirement or not, but we do things together and apart and don't mind. He is going to get DD and I a boat so we can fish. We have been married 46 years and have found ways to work out what we like to do together and apart. And yes, people think we are very strange, but it works for us. And we are both happy.