Road triple cranks with 74BCD have a minimum inner ring size of 24T. You can get down to 22 by swapping for a mountain crank set. I'm uncertain whether you can effectively use your current short cage dérailleur by avoiding small-small cross chaining. Gear ratio overlap between inner and middle chainrings will be limited by rear dérailleur capacity; however no damage is possible, so I would swap out the cassette first and give it a try. If this is not enough, swap the crank set for a mountain model.

For the lowest gearing currently available, you can get up to 36 in the rear with a 11-36 10 speed cassette, but you would need a new LX or XT Shadow dérailleur and 10 speed shifter.

I have never used my 48-11 high gear while touring. When I'm riding downhill that fast on a loaded bike I'm usually unweighing the saddle for safety.