First off you would have to buy new shifters since the STI won't mount on flat bars.. I doubt 26" would mount heigh enough for the brakes, probably easiest to put Cyclocross tires on the current wheelset. The geometry is not designed for a suspension fork so not sure if that would work at all since it would raise the front end a bit and they use 26" tires, you could get a Cyclocross Suspension fork since they take 700c tires and use Cyclocross tires. Basicaly you are converting it to a cyclocross tandem more then anything, and just leave the drop bars If you are just doing trail riding I would just put on Cyclocross tires and leave everything else as is.