First, what fuels (butane, propane, Esbit, alcohol) you are you interested in?
Also, where are you traveling from and to? That can result in lots of local intel like, “Joe’s gas station in Trail City sells butane-mix canisters” or an offer from a BPLer to stash some fuel for you behind that “Curve, 45 mph” warning sign at mile post 87 (I’ve done that for people who wanted to borrow bear spray for their Alaska trip).
Edited to add: Ah, from the sub-forum it appears you’re heading to Philmont. Someone else can answer with more authority, but isn’t there fuel available for purchase when you arrive and some of the resupply points?
Here’s a 15-post discussion on BPL from 2010 with some references to DOT and USPS regulations.
https://backpackinglight.com/forums/topic/39086/#post-1265294
As for flying, unless you’re ready to replace gear at an REI at your destination, I wouldn’t try flying with any white-gas stoves or fuel bottles. It’s just too hard to remove all trace of any odor and a screener could give it a sniff (or not even bother giving it a sniff) and reject it. Butane and propane stove heads have always been fine for me – just air them out beforehand, maybe in the sun. Then source your fuel at your destination.
For USPS mailing, there are lots of regs, but in my experience (shipping radioactive compounds and toxic waste samples and receiving fuels) it all seems to be on the honor system. They ask you if there’s “anything flammable, perishable, or any lithium batteries”, you say “no” and they accept it. Stuff I’ve shipped that was completely safe and within the rules, but would have looked very suspicious on an x-ray (or Geiger counter) has never been opened and inspected.
If you go all Unibomber and drop a package in a post box (not allowed over 11 ounces) with stamps on it, that attracts more attention than going to the counter at the post office.
You can buy butane canisters on Amazon from multiple vendors if you’re in the 48 states. It’s supposed to go surface, and could be delivered to “John O, General Delivery, Damascus, VA 24236”. Call ahead to your hotel but I’ve sent stuff to “John O, Hotel guest July 4-6, Best Western Hotel, Damascus, VA 24236” when it was someone else and when it was me and then picked it up when I checked in. A few Amazon vendors, seemingly garage operations, seem to ignore USPS surface-only rules (presumably by lying when they drop off the packages) because they’ll ship butane canisters to the Aleutian Islands.
USPS and Fedex and Airline cargo are more tightly run and if you don’t have an account with them or are a “known shipper”, bring your photo ID and there are still many limitations – lots of consumer items can’t go as airline freight.
Then, going home, just reverse the process (again, problematic with white gas). Or not – I’ve got stashes of stoves and fuels in a various places in AK and CA with friends or at the lodging or carefully wrapped up and stashed out of doors.
Also, at some point, a $17 BRS-3000T or a $5 cat-can alcohol stove off of eBay might be easier than all the time and bother shipping stuff around, even if you throw it away or leave it in a hiker box or with a note saying “couldn’t fly home with it, it’s free” at the trailhead. A local car rental business in Cordova, Alaska (everyone flies in and flies out to fish or hunt) has a cool system: they have a few drawers labelled, “Need it? Take it. Can’t fly home with it? Leave it for someone else.” and there’s bear spray, fuel, DEET, etc that people borrow, use a bit of, and return when they depart.
I’ve got lots of other thoughts about alcohol if that’s your fuel of choice. P.S. alcohol is perhaps the easiest fuel to use while traveling.
Very short version: see if you can get what you want delivered from Amazon Prime. If so, you’re done.
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