Which type of Mustang are you thinking of getting? I will be there in my 2007 mustang and last time there were quite a few ranging from old to new. There seem to be a few around this area
I am near jnc 8 of the m25 so was thinking of leaving around 7-730. Take in some nice twisty roads maybe via goodwood and the Hindhead tunnel to make some noise and get to Walton bridge around 9ish.