How many spokes in the rear wheel? If less than 36 I would get a new properly hand built and tensioned rear wheel with 36 spokes. You are basically doing loaded touring. Double butted spokes might not be a bad idea either. My strongest wheels are 700c, 14/15/14 ga spokes 36 hole eyelet rims. My current favorite are the Sun-Ringle CR-18, Mavic makes some stronger ones that are all but bullet proof.
Aaron
