TfL appear to have rolled out their new website this evening (the one that’s been in beta for ages). I still need to look around properly, but the best news is that they have finally removed the button for alternate fares. You now get all options straight away. They still don’t describe the default route, but at least you get all the others so you can see if any of them describe the route you were planning to use.
Single fare finder: http://www.tfl.gov.uk/fares-and-payments/fares/single-fare-finder
Tube, DLR & Overground fares: http://www.tfl.gov.uk/fares-and-payments/fares
Overall fares and payments portal: http://www.tfl.gov.uk/fares-and-payments