Hi Gavin,
Oban is a great place - one of my favourites. CC site at North Ledaig is excellent with every van getting a sea view. Toilets/showers to usual impeccable club standards. Good site shop. Sunsets over Mull are spectacular!
The Divers site is closer to the town and a good site and there is a site at Ganavan Sands but this would not be my choice.
The town of Oban has a lot to offer - leisure centre, swimming pool and a cinema for wet days, good range of shops and, of course Oban is a main ferry terminal for CalMac so that there are a number of opportunities for sails or cruises - as well as a number of small boat cruises to see seals etc.
Make a point of visiting the caravan accessory shop in Benderloch, a couple of miles up the road from Ledaig. Its an Aladdin's cave! I was in there once and the customer in front of me was telling the owner that he always knew he would find what he wanted there. I said that I knew I'd always find something I never knew I wanted!
Enjoy Oban.
Rob S.