Can someone give me some pointers on what issues I may have swapping a FSA Gossamer triple crank and BB to a MTB crank & BB? The bike is a Jamis Aurora Elite that comes standard with the FSA Gossamer and FSA Mega Exo, external bearing BB, but while that is fine for regular riding, the gearing is too high for touring, so I want to be able to change it to a MTB crank & BB.

The bike also comes standard with a Shimano CS-5600, 10-speed, 12-27 freewheel that will also have to go. The rear derailleur is an Ultegra triple.

Is the answer to go (for instance) to an XT crank, BB and freewheel? Might there be compatibility issues with the frame and BB? I've never done this before (you might have guessed) so thanks for any tips about where I could go horribly wrong.