Sorry to hear of your loss. That must be really difficult but glad to see you continuing your plans. Best of luck.
Regarding the trailer.... Your setup sounds nice and I'm sure you'll be happy with that. Pulling a trailer behind the Monty is not a good idea. It will most likely void your warranty. You might try doing a search here on the Forum since I know there have been several threads about this topic. And there are folks who do the double towing and do so without any stated problems. In addition it is, as you pointed out, illegal in about half the states. I do not know which ones. There are lists that indicate which are legal vs illegal. Also you will need, of course, the proper drivers license.
Good luck and join us in Quartzsite in January for the annual circling of the Monties. We had over 50 rigs show up last January.
Have fun and enjoy.