It's going to depend on your true preference. I will say if you are going to load the bike down, I'd be going for something with durable rims and tires rather than something for performance.
You will probably end up buying something used as the new market is unaffordable (Rans Phoenix LWB for $4500? Puleeze!) and the used market is quite full of bikes. If you are looking for a Long wheelbase (LWB), you are down to a Rans Stratus of some sort or A Tour Easy. SWB, well, I would go with a VRex. I would run tires of 1.5" wide, probably Schwalbe marathons as they roll smooth and are fairly durable as far as thorns and such.
If you are anwhere close to Ohio, I'd be happy to let you test ride my bikes to see what you are partial to. I have a LWB, a SWB, and a trike.