Hi Lewis!
Your tablet experience mirrors my own; no typos, though, so you're doing much better than I did! 'Thought one might do for tour use, but nah, I need a keyboard for writing. I did find the tablet okay for consuming content, just not for creating it at production levels, and it was hard to hold and type on without a table. The glossy screen didn't help much outdoors, either. Found what I needed in a netbook with nonglare screen.
As for the gearing, I would suggest considering a 44/32/22 Deore chainset. One came on Sherpa, and I selected the same crank again for the Nomad and have been very pleased both times, though it is only fair to warn you that Shimano's external-bearing BBs are generally much shorter-lived than an internal-bearing unit. I did budget for a Phil Wood bottom bracket for when the Shimano wears out. My plan is to use the original BB on my next tour, then switch to the Phil on my return. The Phil unit has a reputation for long life and is the subject of many good reviews over at the MTBR forum.
If you do go the route of a new crankset with 44/32/22 gearing
and wish to avoid HollowTech external-bearing BBs, there is an alternative at a very reasonable price: Shimano make a very similar looking crank in the Alivio, which pairs nicely with a UN-55 sealed BB. This model is surprisingly good, shares the same BCD/PCD as the Deore, looks much the same, and is the go-to replacement crankset for many in The Netherlands who want to replace an external-BB Deore HollowTech II. The model to consider is the
square-taper version of the Alivio, as the Octalink version can be problematic:
http://www.amazon.com/Shimano-Alivio-Mountain-Bicycle-Crankset/dp/B00485OLT4 Not the "best" of chainsets, but a very nice-looking, entirely serviceable one for very little cost that will give years of good service. You might say it punches above its weight class. It does come with the economy of steel 'rings, but they are replaceable and would last a good long time on their own. Just a thought at the lower-end of the price spectrum if you hadn't thought about it.
My thinking, Lewis, is that an entire chainset (crankarms and three 'rings) can be had for little more than the three chainrings, and if purchases in square-taper, might well fit your existing BB and pretty much eliminates any concerns about untimely BB wear.
If you do replace the chainset, then you'll have a nice selection of low gears to meet your needs, and can always shift up to the middle or high 'rings as speedful needs demand.
Lewis, one of the most valuable realizations I came to was a realistic assessment of my gearing needs. I can count on the fingers of one hand the number of times I've actually used a gear above 82 gear-inches, so I decided to set ~80 gear-inches as the maximum on my Rohloff-equipped Nomad, allowing me to shift the whole range downward, picking up two really useful gears even lower than my usual 19 -- a 17" and a 15". While the process isn't quite so straghtforward with derailleur gearing, I can tell you I never once regretted the 44/32/22 chainset on Sherpa and went through three cassettes before happily settling on my 12-36 as ideal, giving me gearing very close to what I now enjoy on the Nomad. I had a realistically low set of high gears, and this helped me achieve the really low-end gears I needed. It was such a joy to be able to climb hills in my 3rd from lowest gearing combo unladen, knowing I has one or two more as "bail-out" options if needed when loaded. I so admire riders like Jawine who really can and do pull very high gears, but alas, that's not for me. I can substitute a fast, light cadence with lower gears and keep the warranty intact on some formerly damaged knees.
Just a few thoughts to consider. Others will be along shortly with good ideas of their own; somewhere among them something may touch a chord to help you with your decision.
All the best,
Dan.
