You should get a good turn out as right next to the nutters around Brum
Have a look at the events pages and see where there is a gap or maybe where there is a meet close by that could add your event into a visit
Camping at the same time seams to go down well with the BM crowd so maybe look at it as day visit followed by night somewhere, good to make it into a raise funds for the charity there
Just a couple of thoughts and wish you all the best. Date/work depending I might try come down as sounds a good day out.