With regards to a comuter or park and ride scheme, for this to be successful, you would have to run every day and would either need a lot of volunteers or more paid staff. Swannage seems to have made a good job of it to a certain extent, weardale have tried and given up, keighley and worth are still looking in to it, the last I heard. As to extending either to oundle or heading towards seaton junction, it's going to be expensive both in the extending and the running and maintaining of. Oundle maybe just about viable, but being on the edge of the town, would need a decent amount of land available for parking. Going to nassington and kingscliffe would be good for the enthusiasts as there are decent gradients on that stretch, but wether kingscliffe is a viable destination, I don't know.