At that stage perhaps consider upgrading to a tandem and bring a mechanic along
OP asked about long tours in isolated spots. They're the kind of tours I'd consider upgrading my components before departure, especially if 10 years old and well used. It's good practise if nothing else.
Yeah to a degree I agree with you but going out on long remote tour I would rather go out with equipment I have ridden for a while and have faith in as much as you can
Just as a side note these are the spare parts I tour uk with or less than a couple of weeks
2 inner tubes
Patch repair kit
Pedro's tyre leavers
Pedro's downhill tyer leaver for wife's bike tyres are horrible to get off
2 brake cables
2 gear cables
Pedro's hex set dont like multi tools dont find them good enough
Park chain breaker
Small spanner
Couple of screw drivers
Kmc chain
2 break blocks
Couple of spare spokes and spoke key
Spare nut and bolts cable ties couple of rags
Park tool tyre boot
Muc off oil
This is what's in my bag this afternoon
For longer or more remote tours I add
Pedal spanner
Cassette remover park fr5
Chain whip
Large spanner
Bottom bracket remover spare bottom bracket
New cassette and just inner ring from chainset
Extra set of break blocks and extra chain and an extra inner tube and a folding tyre
Depending we I am heading dry or wet lube
And I have just ordered a new rear mech