Ben...Happy to hear you are coming this side for a holiday. I am from North Yorkshire and will tell you things are so very different here!
Have you considered a smaller motor home? I am thinking if you have never towed you may be more comfortable. You will be climbing mountains, crossing prairies, taking ferries and traveling on highways like none back home.
We have traveller's across Canada and we spent almost 2 months, not really stopping much to visit places. Choose your route carefully. For instance England fits into Ontario 8 times and 5 times into Texas. Distances are all lot farther than you think.