There isn't much to add to all the other reviews; it is well worth the exhausting climbs. Get a lift in a local vehicle to Pulna from Govindghat- the locals are the only ones who can use this road - the climb to Ghangaria is now halved. Get a horse to carry heavy bags from Pulna - its worth the small cost. We all found the walk very tiring and apart from the horses and locals nobody was rushing past us.
GET A GUIDE - without one you will not understand the valley and its flora and fauna. We hired Rajneesh Chauhan for our group of 4 - he has a shop in Ghangaria (9927594671). What he didn't know about the valley wasn't worth knowing - he also made us lunch from what he carried and from what he picked along the way - It was delicious. He knew what we could taste and found us lots to sample along the way. We saw many large groups walk past plants as the guides couldn't get them all to see the small delicate plants. There was only one location for Blue Poppies close to the path and many visitors never saw them. Your efforts to get there will be rewarded if you are with a guide in a small group of about 4.