As no on seems to be answering, I'll take a very poor shot at it:
- Any crosser should take 35mm rubber, but the Cross Check goes quite a bit bigger.
- Re. front racks: the latest Cross Check will take one, but not previous years - at least not without bodging. So check carefully exactly what you are buying:
http://www.surlybikes.com/bikes/cross_check_complete/
Also: take a look at the complete cross bikes that BikesDirect sells on their internet site. You might well do better buying one of these and selling your road bike complete.