If I was setting up a follow-road route for an audax, I'd start by working out on a map where the route was meant to go. I'd then set the routing to car/shortest distance and click on each of the controls in turn, then check the route it came up with against where the route was meant to be. In practice, the specified route often isn't the shortest way between controls, so it's quite likely that there would be differences. In that case I'd add extra points between the controls to force the route onto the correct roads. After downloading the route onto the GPS, I'd check it again in case of any differences in routes selected, and correct and download again if necessary.
I've just tried this for the Elenith (picked 'cos I know where it goes).
I added 3 extra points:
at Bewdley to force the outwards route onto the bypass as per the route sheet (though through town is allowed)
at Pembridge (shortest route between Rhayader and Kingsland is via the A448, Presteigne and Shobdon)
at Leominster (shortest route back to the finish is to cut up to Yarpole and follow the outwards route)
There were also short cuts at Orleton and just before Kingsland that save 100m and 500m respectively. I didn't bother doing anything about these. I've certainly seen people using the Kingsland short cut - it's handy for getting to the control before the others in your group.
Checking the route on the GPS, the only difference to the Mapsource routing is that it returns to the centre of Tregaron on leaving the control - 200m extra
Total time: 10 mins
Here's the route if anyone wants it (saved as gpx from Mapsource and loads of rubbish deleted):
<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<gpx xmlns="
http://www.topografix.com/GPX/1/1" creator="MapSource 6.13.7" version="1.1" xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="
GPX 1.1 Schema Documentation http://www.topografix.com/GPX/1/1/gpx.xsd">
<metadata> <bounds maxlat="52.4110347" maxlon="-2.2548151" minlat="52.1336031" minlon="-3.9367032"/> </metadata>
<wpt lat="52.1483945" lon="-3.4034112"> <name>Builth</name> </wpt>
<wpt lat="52.2786512" lon="-3.0661252"> <name>Discoed</name> </wpt>
<wpt lat="52.4110347" lon="-2.2550514"> <name>Finish</name> </wpt>
<wpt lat="52.2483628" lon="-2.8121301"> <name>Kingsland</name> </wpt>
<wpt lat="52.3004948" lon="-3.5103095"> <name>Rhayader</name> </wpt>
<wpt lat="52.2428656" lon="-2.8834391"> <name>Shobdon</name> </wpt>
<wpt lat="52.1994981" lon="-3.7520901"> <name>Staircase</name> </wpt>
<wpt lat="52.4107548" lon="-2.2549750"> <name>Start</name> </wpt>
<wpt lat="52.2219041" lon="-3.9367032"> <name>Tregaron</name> </wpt>
<rte>
<name>Elenith</name>
<rtept lat="52.4107548" lon="-2.2549750"> <name>Start</name> </rtept>
<rtept lat="52.3765576" lon="-2.2997362"> <name>2221</name> </rtept>
<rtept lat="52.2428656" lon="-2.8834391"> <name>Shobdon</name> </rtept>
<rtept lat="52.2786512" lon="-3.0661252"> <name>Discoed</name> </rtept>
<rtept lat="52.1483945" lon="-3.4034112"> <name>Builth</name> </rtept>
<rtept lat="52.1994981" lon="-3.7520901"> <name>Staircase</name> </rtept>
<rtept lat="52.2219041" lon="-3.9367032"> <name>Tregaron</name> </rtept>
<rtept lat="52.3004948" lon="-3.5103095"> <name>Rhayader</name> </rtept>
<rtept lat="52.2178582" lon="-2.8967095"> <name>2427</name> </rtept>
<rtept lat="52.2483628" lon="-2.8121301"> <name>Kingsland</name> </rtept>
<rtept lat="52.2247741" lon="-2.7555569"> <name>2466</name> </rtept>
<rtept lat="52.4110347" lon="-2.2550514"> <name>Finish</name> </rtept>
</rte>
</gpx>