First, I am an 81-year-old single grandmother, and I have been full-time traveling alone for over 12 years. I do not camp in the desert or forest alone, but rather I stay in national, state, and county campgrounds. In 12 years, no one has ever bothered me. I felt slightly unsafe once as some men down the campground road had been drinking all day, but I left the next morning. But that is all that has happened to me.
However, you do have to expect things like blown or flat tires, or things inside the RV that stop working--like maybe your refrigerator will need to be repaired, or you will need a new water pump. But you'd have that in a house also. And there are hundreds, if not thousands, of videos on the internet made by fellow campers on things like how to replace a toilet or get one unplugged.
Before you agree to buy anything, the MOST IMPORTANT THING is to get it inspected by an outside inspector! There are people called mobile RV repairmen who can come to a campground to fix things. Many of them have gone to training programs and been certified as technicians, so you should get one of these people to inspect your rig BEFORE you buy it.
Especially if you buy used, you can make some incredibly expensive mistakes if you try to save money by skipping an outside inspection. After several friends told her to get an inspection, one of my friends ignored the advice and bought a motorhome in Arizona. It broke down on the way back to California, and had to be towed. On the way, she found several things that the owner/dealer had lied to her about. The result? She sold it for a big loss through a consignment broker. The next rig she bought she did get inspected, and she is happy with it.
Also, you sound a bit younger, but there are a lot of us older women driving and traveling alone in motorhomes or other types of RVs. In fact, I believe the ratio is about three or four women to every older man traveling alone, so it has to be pretty safe.