Nice how you were able to carry one as a spare vehicle. Even though they're small, it doesn't affect their ability to go a lot of places that larger, more power vehicles do, and if a situation is too much for the trike, they can be physically drug through and over a bunch of stuff.
I've personally walked them across fast flowing rivers that were chest high, with the aid of another person. Two people, both riding trikes, means extra help when the going gets rough. Drag one up, across, or through something, then go back and get the other one, and both are on their way. If the situation was dire, I'd rather be on a trike than something so large and heavy, it becomes a liability in and of itself.
The story of three wheels and a man...