I work in MK, and you are pretty central to the UK for any ride outs and race meets. Dont forget your Silverstone tickets lol.
Cornwall does have some nice roads, lived there for 20 years. Dont go on the Isle of Wight, its dire, the roads are terrible. Id go for a nice ride round Kent, good roads, or even pop on the EuroTunnel and spend a few days in Normandy. Lovely roads, lovely scenery, lovely weather. Its like Hampshire and Dorset but the locals have a funny accent. lol
I went to Le Mans last year, took a day to get there with plenty of stops, lovely roads. Did a toll road and then did the A roads, brilliant fun.