A couple thoughts perhaps alternatives to full time Rving.
From your second post I wonder where the two older kids will be during this RV adventure? Will they be with you, with your dh, or perhaps with another family member?
My kids go to an international private school grades 7-12. The school nurse gets free accommodation and children of staff attend for free. That would take care of employment, accommodation and a better education for the older kids. One of the teachers has a now 2 year old who has lived on campus since birth and has 150 teens who love him to bits.
Summer camps: here in BC a summer camp needs to have a nurse on staff. Last year the camp my daughter attended had a single mother nurse with a 9 years old dd with her. Once again employment, accommodation and a great place for kids all rolled in one.
I had huge challenges finding good daycare for my second child. He is 10 years younger than his brother and I had to work full time. For him, it was not good to change daycare, but we had to 5 times before he was 2 years old. All the daycares were licensed, but after the first one lost its funding it was almost impossible to find another good place for him.
Because of what we went through with ds2, I would hesitate to plan on moving a child from daycare to daycare when that young.
Later two of my friends watched the kids after school.
Good luck with your future plans, you know your family best and will make the best decision for your situation.