I did the route in July, after the original event was cancelled in March due to forecast "Beast from the East" blizzards. I also did a couple of the hills on the morning of the day of cancellation, having already arrived. It was rather an experience in rapidly icing surfaces and fierce winds on Pole Bank. Apparently blizzards and deep snowdrifts did materialise later on. Not quite the conditions in July:
Photos from SW50 in July
For the event, the organisers had arranged parking in Craven Arms quite near the Discovery Centre.
If you book a B&B and want breakfast, it is worth checking that they actually provide it: mine near Much Wenlock did not.
Re. the route, the organisers describe the last section from Hopesay Hill in terms suggesting it is easy but I would say (in a night section) it was not straightforward due to the lack of obvious paths together with rough pitted ground. The first section before the Shropshire Way proper, at least before Wenlock Edge, would have been worth a recce as the route description was not very detailed. Otherwise navigation was not really problematic as it was a case of following the Shropshire Way signs but a few CBs would have been helpful e.g. on the ascent of Linley Hill.