Bo,
Knowing your situation as I do, I would recommend a twin axle camping trailer that you could modify to fit some very needed things in. A camping trailer would give you a toilet (makes women happy), usually has hot shower and a reasonable cooking area, along with built in lighting. Built in water heater, water and black water storage would be far easier to use than jugs in a truck. Most have heat and AC, some have their own generators.
My personal feelings are over the long term, it may be more workable than a rental truck. If TSHTF while you are on the boat can the wife load what you want in the truck alone? You could move some of the stuff you have stored in the garage and store it in the trailer, ready to go, if needed.
Camping trailers are very reasonable right now price wise.
Stu