To get here one has to travel approx 250 km by road from Rishikesh which is the nearest railway station and then trek up further 15 km. One can use ponies or Helicopter to skip trekking. It is the base camp for valley of flowers trek. You can see more info about Ghangaria here.
Ghangaria is the starting point of the trek to Valley of Flowers; and to the Sikh Pilgrim center of Hemkund. The place has facilities for transit accommodation and one can get porters and other logistical facilities like horses etc. To get to the place one has to trek 21 km from the main motorable road. The trekking is not very easy; the place probably is at a height of around 10,000 ft.
There is not much to buy at Ghangaria , but you can buy books and CD about valley of flowers at Eco Development Committee EDC Bhyuandar.
If you are suppose to arrive ghangariya in evening time than you should get a resort here because there is no arrangements of staying done in the park.