Without knowing your age or financial situation, based on what you've typed here, I'd sell both boats and rehab your current RV into as close to what you want as you can get.
Short of dropping a boatload (pun intended) of cash into a massively depreciating asset (new truck and camper) it seems like your best option.
Despite the Cat being an awesome rig with a ton of potential, it just doesn't sound like that's how you want to travel right now.
Your list is unique, you will most likely not find something setup like you want anyway, so no matter what direction you take you will be modifying and changing things. May as well start with something you already own.
If money was unlimited, I'd head over to the forums at expeditionportal.com and check out build threads for some custom built overland rigs. Folks there are doing what you are wanting to do.