Uncle Dave,

I'm slapping my forehead. Duh! What you need is an Xtracycle. I have one. It's attached to a Jamis Exile, a sweet production hardtail. The Xtracycle can carry up to 250 pounds and hold all kinds of odd things. It doesn't require any extra wheels or tires, and it can easily do this sort of trip.

I haven't read this yet, but this should interest you below. It's an account of an off-road wilderness trip using an Xtracycle:
http://www.crazyguyonabike.com/journ..._id=29543&v=4z

Here's a picture from the Crazy Guy website:




And one from the Xtracycle website:



While they are not as cheap as a trailer, they are comparable or cheaper than a trailer, a quality rack, and bags. You don't have to use panniers, any sort of bags will do. They have a longer wheelbase, which changes riding technique in certain ways, but I can tell you from experience that this is an option well worth considering. I'm in NY and my Xtracycle-bike is in CA, so I can't send a pic this moment. Maybe I can find one somewhere...It's set up right now with Nitto Albatross bars and friction thumbshifters. I really like the advantages of friction shifting when using the longer chain length required for an Xtracycle, and I used an 8 speed cassette.

I have use mine to carry everything, including bags of cement, industrial water hoses, mulch, groceries, etc.

Xtracycle Website

You would have no problem carrying 100 pounds with this.

Hope this helps.