Originally Posted by
sedges
Dan! "Being able to carry food and water for a week in arid areas like Big Bend NP or Coronado NF is the goal." That would be desert. I carry and use a purifier. Just to clarify. If there has been rain or snow there may be springs available, but often they are dry. If springs are running and I don't have to carry as much water I could carry more food and stay out in the remote back country roads longer. It just depends on the weather.
jankdc! Thank you for sharing your experience. Under what circumstances were you carrying 4 gallon of water?
I own a BD and my friend toured with a MTB + Xtra by packing both into a large cruiser bike box and shipping them that way. Based on what you have said I think the BD is a better option for hauling gear and the MTB+Xtra for shipping. You can get a BD with S&S couplers so you can split it, but it won't be a cheap upgrade. A touring bike with trailer would also work and depending on the configuration might be very packable.
I don't think an Xtra will be a problem even if it's not as optimal as a BD, but unless you get a big bike box you'll have to ship it as two items - possibly will have to no matter what if you count your touring gear that can go into one of the boxes.
The other thing to think about is a BD is not as big a tandem and folks take planes, trains and buses with them so I'm not sure why a BD wouldn't be work as it's no bigger.