Like the folks said, have your tape measure handy. Also, find a scale and weigh your bike and trike. My 04 Ultra is around 900lbs, I think. (That brain cell has passed on, so I am not sure) If no RV shows around, find a multi line dealer, and take your notebook. You don't have to buy there, and you can be honest with the sales guy what you are doing.
You have lots of reading on this site to get up to speed. Also consider if you will be staying in RV parks, or State Parks, or what your destination is going to look like.
Looking forward to following your journey.