As a newb on the forums I am only offering my probably useless 2 cents.
I believe you are looking at things through rose colored glasses. You have THREE dogs. Strike one. You are having a first baby. You don't know what parenting is about and you think you can manage it with three dogs in a motor home? Admirable thoughts, but I seriously doubt an achievable result. I see the multiple dogs as a large part of the problem and the idealism of new parents as another. I would seriously suggest that before you take the financial plunge you rent a typical unit for a full week and see how it works out. I understand that you won't have tenants lined up if you want to take off, but on the flip side you won't have a huge motor home with an equally huge mortgage that you are looking to unload because making the payments doesn't fit into the budget and/or the tenants have trashed your home. You have a great dream, but I think your reality will be substantially different. Living on a boat without kids and with others is WAY different than Junior and the dogs in a MH for a week of heavy rain and cool temperatures (A once every hundred year phenomenon!)
My kids are 37 and 42 so I've "been there, done that" as far as raising kids are concerned. I love them and they were great kids are are even better adults, but I am watching my son with my grandson (almost 4) and listening to his idealism getting slightly refocused.
If you do jump in, I wish you all the best. And I seriously hope you will keep all of us "in the loop" as time progresses, including little Johnny's (or Janies) first birthday in the MH.