If you are planning to heat/cook anything, I also recommend some type of small mimi stove that Scott mentioned. We use one all the time. You also can get a set of pans that fold and stack into each other that doesn't take up much more room than a coffee cup.
LL, what about one of those car top carriers/boxes I see being used. Will they let you do that? Don't know anything about them, just a thought....
The shows we travel to, I see guys put pvc pipe tied to the roof tops to store long stuff in. Caps on ends. Might be a second alternative if room gets critical.
