Harrisons
Ffordes
Like with anything on ebay you have to judge it. Buying an entry level model you can imagine the sale is because someone is moving up the body ladder.
From what I understand the Nikon kit lens is well reviewed. By 'ok' for climbing shots it depends what you want. 18mm isn't super wide on a crop body, nor is 55mm on a crop (x1.5 for Nikon) particularly long. Its a good place to start.
Yes, HD footage from DSLRs is pretty stunning for the cost. Focussing is manual, if you want point and shoot auto focussing options you don't want one for video!