Does your 5er have twin beds as some of that year did? Is it possible to build extra storage under those beds for your supplies?
Also, does it have two nice rockers in the living room, and do you use the couch...We didn't use our couch when we had two rockers.. Our couch could have been removed and a neat, as big as possible and even pretty storage unit put in it's place.
Also, when we had our Avion 5er...we used one of those canvas "curtains" to cordon off the area under the front overhang of the 5er, and that made a BIG storage area. We put a cheapie wood "flat" floor to keep things up out of the rain.. and stacked heavy duty plastic storage containers on top of that..The whole area was stacked in a circle with the "walkway" in the middle...allowing easy access to all of them.
Are you going to buy your Wyoming Ranch immediately, and live in the RV while you build a home and mule barn? If so you could buy/build a storage/craft building as well..
In some states you can legally pull two trailers IF one of them is a 5th wheel. So if you are not moving often, you could get a cargo trailer and turn that into your craft storage and workroom. I know carpenters who do this and take this traveling "office/storage area to their jobs.. They have storage for saws...cabinets for supplies...a desk for working on figuring materials or checking out the blueprints...etc..
Any of these sound appealing?
Happy "craft room" hunting!