I agree with Tom for your route. We came from Miami just the way Tom recommends. We live in Brunswick which is just north of Portland.
We use to travel by car and pull a boat behind us and we have gone the other way thru NJ, Ny up 95. Since we have the motor home we went Toms way and what a beautiful trip. The tunnels do not want you to go thru them with propane. The bridges traffic is always a mess, plus all the tolls.
I will tell you that some of the toll plaza's are pretty tight, but you can make it if you go slow.
I also agree about planning your travels thru the NE avoiding Friday thru Sunday. It's just not worth the time spent in traffic.
When our kids come up from Ma. on the weekends, they always leave on Monday or they travel after the dinner hour on Sunday and get home faster than leaving early on Sunday.
Maine is a beautiful state and the people are great. The food is even better and you won't want to leave.
The season for the Change of the leaves is coming soon. We haven't seen any change yet but it's coming.
If you plan on going to Bar Harbor, there is a National park there named Acadia. We have driven by car not by motor home.
We are going to be leaving here next week and we think we are going to drive up to the Great Lakes and see the changing of leaves on that route. We are going to keep going until the weather makes us head back south to Florida.
You will never forget your trip to Maine. Have a great time and safe travel.