in all seriousness Lew, as you are someone who has toured before a lot, you know about gearing and the weight of a bike.
Ive toured extensively in hilly mountainy terrain with up to maybe 50 55 lbs of stuff, and one of my bikes has a low gear of 16.7 gear inches (specifically a 26in bike, with a 22t front and 34t rear on 2in tires)

if you add a trailer and a 100lb pooch, and x lbs for the trailer, you are going to want some serious low gearing, or lets put it this way, your legs and knees are going to want some darn low gearing.
Sure, it depends on the terrain, but short steep hills happen, and while he she can walk at times, in my experience, you will still want to use a mountain bike crank, ie 44 or 42/32/22, and a good sized cassette also, to 34 or 36.

lets also be realistic about the jumps betwween shifts on your older bike, with 6 speed, you may possibly have some larger percentage jumps between shifts, and with all that weight, it could be a hell of a burden---think 18 wheeler trucks and their closely spaced gears, its like us with a touring bike, add on a heavy dog and well.....something to take into consideration and at least be realistic about the physical challenge of hauling a shedload more weight than you have in the past (not to mention, when you were younger, and most likely a lot stronger, no offence, but as we age, we arent as strong, let alone perhaps with effect from your unlucky medical stuff.

whatever you look into, a mtn crank will make life a lot more enjoyable. Im totally sold on them for heavy loaded touring and they work perfectly for the speeds we chug along at with a heavy bike.