Mr Happy - The area around Selby is pretty flat and a lot of it is under cultivation, so there isn't much walking in the imediate vicinity. That said, the George & Dragon keeps a collection of booklets with circular walks around bits of Yorkshire. Some of these are not too far from where we will be based. As you head towards Leeds the countryside becomes lumpier but more rolling than hilly.
As mentioned, we will not be far from the M62 (about 30/40 minutes drive will get you to places such as Hebden Bridge where there are REAL hills. If you take the A1 North you can get then cut across to the Yorkshire Dales. There is some good hill walking at places such as Kettlewell in Upper Wharfedale.
Camping facilities will be basic as we are not on official campsites, it is just land belonging to farmers near to the pub.
If you need to discuss anything in greater detail, send me a MudcatMail Personal Message, and I can give you a phone number.
Quack!
Geoff.