The only place I concerned about flats is the rear tire, because all of my gear will mostly on the back, so I will add a Panaracer FlatAway liner which only adds about 30 grams but that liner is extremely tough, more so than any plastic liner on the market.
.... I don't want to be buying a tire on the road if I can help it, but that maybe what I'll need to do.
First, I would highly suggest you more evenly load your gear. If you are not using front panniers, putting most of your weight on the rear wheel is a recipe for bike shimmy which can be dangerous especially on the mountain downhills. If you are using front panniers, shift the heavy stuff to the front, i.e. food, tool kits, etc. I actually strive for a 50/50 balance and I can then ride no-hands believe it or not. Can't do the Peter Sagan wheelie though

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Secondly, just buy a foldable tire before you go and have someone mail it to you care of General Delivery to any US Post Office. I use the General Delivery quite often on my longer trips as I take a BUNCH of meds (transplant) so need to replenish then every 3 weeks. It has never failed me when I use the proper type, i.e. a town with a population between 1,000 and 4,000 people so they only have 1 post office but it has regular 9-5 hours including some Saturdays and the small-town "how can I help you" attitude is really helpful. I have even had one Post Mistress (is that the correct term??) deliver it to me on a Sunday since I got off my schedule by two days and the next day was Labor Day. Since then I have learned to always try to target the pickup time for a Tuesday (it can arrive up to 30 days before you pick it up). That way if I am a day early or up to 3 days late, no big deal.
Sure it adds some cost if you only ship a tire, but then make yourself a care package, i.e., tubes, tires, new shirt, food/candy bars you can only get at home, etc. then the cost become acceptable.
Final point on General Delivery is that if it needs to be fowarded because you can't pick it up on-time, be sure to use priority or at least First Class as it will be forwarded for free.
Tailwinds, John