SB - signposting unlikely, particularly as runners aren't allowed to park in the Royal Forest car park. Parking is recommended in nearby roads including Bury Road. The Orion Harriers website has a bit more information including a map link http://www.orionharriers.org.uk/hq.htm
The Royal Forest Hotel, at the back of which you will find the start, is a whopping great half-timbered pub / hotel on Rangers Road approximately 10 minutes very straightforward walk from Chingford station so if you aim for Chingford you can't go too far wrong. Bury Road is even nearer the station.
I seem to recall 2 water stations last year but it is cups not bottles so you may want to bring some of of your own if you think you need more hydration.
I'm going for my light, not overly grippy trail shoes cos I'm saving the road shoes for the Hastings half on Sunday