Interesting point RE brevet card info vs route sheet info - I've never bothered to carry a route sheet (I'm firmly part of Generation GPS, and I'd have to buy a printer whose exclusive use would be printing route sheets). I'm relatively new to audax and I'd assumed the gpx and route sheet contained the same information: how to navigate between the controls. Maybe I need to buy a printer and learn more about this "one true way" you speak of...
The GPX and route sheet do take you on the same route, both are perfectly fine for navigating the course, but the GPX file is not usually flagged with the info locations. so you need to identify them from either the brevet card or the route sheet.
The brevet card may say "at the t junction; distance to Llanfairpwllgwyngyllgogogoch", "wetwang; last collection time on postbox" or "Nether Wallop; name of pub", but by reading the route sheet you will know for sure which T junction or location you should be at.
By spending some time creating your own bespoke gpx files, aside from gaining a better understanding of where you will be riding, it will be impossible to ride past an info. Many times I have seen riders ahead of me ride straight past an info, or seen them taking down information before they have reached the info.
Of course this does not help if the info isn't actually on the route. In such cases I just file this under "organisers rides I do not wish to enter in the future", because life is too short to be wandering around a village or town at 2am in the rain trying to find something which should have been on the route.