We've stayed at Clumber Park many times and just love the location and the daily walk around the lake (around 6-7 miles if you walk from the campsite and all the way around the lake, though there are lots of options if you don't want to walk as far).  Our dogs absolutely love the walks there. We'd recommend visiting the NT Tea Room by the walled kitchen garden (open weekends and holiday periods I believe) as it's a little more relaxed and less busy than the cafe in the centre.  There's lots of outdoor seating if you have dogs; the centrally located cafe now has a small room which is dog friendly which is new since the last visit. The walled garden also features the world's second largest selection of Rhubarb varieties (!) We stayed over the Easter period so the site was full and I pity the wardens who had to clean up some of the mess left in the toilets, it always seems to be the same at Clumber when it's busy.  You get a wide variety of humanity staying there so suffice to say we enjoyed being able to retreat to the vast expanse of the park! There's a WiFi signal onsite but there appears to be very little bandwidth to the site so if you do succeed in logging in (which takes perseverance) then don't expect to be able to do much browsing.  The CC website and Met Office were both just about usable and don't need a login to work.  The phone signal at the site and around the park is limited and intermittent so don't rely on it to make arrangements if you have friends visiting! It was a shame to hear that bike thefts are still happening.