Short of completely changing to 9spd (to use 12-36 cassette), I think your best bet is the 11-34 cassette, with a 24t small ring in place of your 26t. The 24t ring to 34t cog will give you a low gear good for most hills. I was using this same combo on my touring bike with trailer, and hauling 50lbs of gear (33lbs bike-27lbs trailer, 170lbs-me). I switched cranks to be able to use a 22t small gear, but ONLY because I want to have the ability to haul more weight, if necessary. For racks/panniers and a normal load, the 24/24 combo should work very well. As far as the 'capacity' of the FD and RD, Shimano is VERY conservative with their numbers. I use a 24/34/52 crank with an 11-34 9spd-XTR RD and XT FD. No problems with their shifting.