Don't get me wrong 414, your idea is a great one and should happen in addition to CD5
Indeed in WA their "race" meetings are often unscored, i.e. races without results, to try and engender the fun aspect over serious racing.
There is no reason on earth why affiliated clubs shouldn't promote non-competitive Vintage dirt bike fun days, show'n'shines and swap meets. I'm sure a lot of the older guys that just don't want the hassle of racing would flock to those types of meetings.
But it probably does need to be done by affiliated clubs, because the risks a private individual or landowner would face from litigation without appropriate insurance would be very high.
Here's an idea - what about a vintage bike Poker Run?