Some advice. Don't start out with a 45' RV. It will be a handful!
Other advice, for the first trip, I would ask that you leave the huge trailer behind. I know it has it's purpose, but really, it is a lot to start trying to back that large of a trailer into a small camping site. If you really need to take a car, then try renting a tow dolly, I think you will find it much easier to park than the 22' long trailer.
It might be best if you have a destination in mind to just take the motorhome solo, and plan on bringing along all your meals, and other things with you. Sightsee with the RV. You will really get a hang for driving the RV before attaching a 22' long trailer to it.
Remember how difficult it can be to get a 34' RV into most sites, and then think 10 feet longer, and how difficult it can be to back the trailer into your driveway at home, and imagine doing that with the RV at some un-known campsite without any assistance!
While on this camping trip, picture how and where you will park the large trailer at each campsite along the way. It will take planning to figure out where to park that thing. You might have to rent a second site at smaller campgrounds to fit in into the space beside the RV one. Even then, while backing the trailer onto the site, you will be blocking the road for at least 10 minutes. At least you can put down the hydralic jacks to raise the back end, lower the trailer hitch, then drop the RV so you will not need to lift the trailer hitch to undo any WD bars or take off the hitch.
Good luck!
Fred.