In reply to pjj:
climbing shop at Yosemite used to sell Coleman fuel. Which is where I got mine when doing the JMT.
If you want to make sure you could probably order in advance and they'd hold it for you. Remember that the USA is not the land of the free, but the land of the MSR and nearly everyone has a Whisperlite and many will have a Coleman Tilly lamp as well for thier 'back woods experience', so nearly any outdoor store, REI and large Walmart will have Coleman fuel.
Plus if you talk to people leaving the trail in you're best British, or for bonus points Scottish accent, you can probably blag what they haven't used. Obviously not to be relied on.
In general I found the American Trail/ hill goer to be refreshingly more diverse, friendly and talkative than your typical munro party, or uk backpacker.