the refugio in Margalef is run by Jordi the guy who discovered the crags and he also writes the local guidebook. There does not seem to be an obvious place where climbers stay at St Leger, though there is a gite by the main car park where some climbers stay - it is not as cheap as the refugios in other places though. You can also buy the local guide there. I think it would be quite hard to get there without a car. Most of the crags get lots of sun so even spring and autumn can be quite hot and restrict you to the North faces which is more prone too seepage. Frankenjura is great if you like power endurance climbing it is probably one of the best crags in the world.