Actually there seems to be a way round this - I checked with my organiser a few days ago and he confirmed it's possible, a few people have done so and he's happy with it.
If you click on the "Members" tab on the main page on the old site (
http://www.aukweb.net/home/) you'll find that login there is enabled. Once you've done that, it's possible to access useful things such as purchasing brevets. Clearly it's in everyone's interest to get things like this done while it's all quiet, so I hope no-one in authority thinks it's a loophole that has to be closed...
Now you are getting into an area of possible confusion, and I hope I'm not merely adding to it! With a pure DiY by GPS ride, receipts can't be used as backup because the entire route is needed to prove the distance - there's no concept of shortest distance between controls. But if you're doing an established permanent designed to enable receipt-based validation, it may be worth collecting receipts as backup even if you plan to prove the ride using GPS, an option I believe some organisers offer.
With DiY by GPS validation, certainly you can use your home as the start and end control, or if you prefer not to, start your ride at a nearby landmark. The distance between there and your home would then effectively be neutralised. I don't know if anyone does this but I could understand that some might.
With traditional receipt-based validation I think you do have to use a local shop or equivalent. I see a lot of discussion about using selfies as proof of passage and I think this is increasingly used. Acceptability is something to confirm with an individual organiser, but in general they are looking for reasons to validate rather than to reject.
It seems I still haven't got my head around it 
