I have a cross check and it is a great bike, very smooth ride and will be more than sturdy enough for you.. Make sure you follow the rule of buying 1 size smaller than normal.. I ride a 60cm road bike but a 58cm crosscheck fits the same.. The crosscheck is designed to have a higher bb so that is why you need a smaller frame..
The best part of the crosscheck is that you can use 130 or 135mm hubsets, since the rear triangle is 132.5.. I built up a set of touring wheels with XT hubs / 36 hole open pro wheels for a very sturdy wheelset for offroad and light touring..
I would definitely not use the khamsin wheelset that comes with the bike, they would not be robust enough for you.. I would check and see if the bike is campy 9 or 10 speed? It is easily worth 400 sterling as it is built.
I have the same inseam length as you and ride a 58cm and it is a spot on fit..
Last edited by socalrider; 02-06-09 at 04:13 PM.