Right, Stirling seems to be lacking in all year campsite, however I have found 1 - not entirely Stirling but it will get you about 5 miles closer to Crail!
The Woods Caravan Park
telephone: 01259 762802
Diverswell Farm, Fishcross, Alloa. FK10 3AN
I called the guy and at first he said he couldn't take 7 tents, then asked how many would be in a tent - I said it would likely be a maximum of 7 2-man tents - with 2 people it would cost £15.50 for the night.
To be honest, I think I caught him off balance so if this sounds ok, then best give him a shout and book a place. If that is going to be 'home' for the night then pub location needs thinking of as it is a wee bit away...but if the Duke's Pass drive is being considered then I'd also recommend heading up the A9, coming off at Gleneagles and going the back way to the campsite for some more countryside windy roads...
Link to where the campsite is -
http://maps.google.co.uk/maps?f=q&source=s_q&hl=en&q=Alloa,+Clackmannanshire,+United+Kingdom&ie=UTF8&cd=1&geocode=FUBEWAMdWhbG_w&split=0&sll=53.800651,-4.064941&sspn=6.881357,14.941406&ll=56.143732,-3.782043&spn=0.016138,0.03828&t=p&z=15 - It's about a 15 minute drive (if that) from the Uni.
Not sure how to do it but I might be able to produce a Google Earth tracklog file of the suggested drive - let folk see what I'm suggesting? Actually scrap that, I don't know how to do that...proposed route would be -
Stirling Uni -> Bridge of Allan (BofA)
BofA -> Keir Roundabout on M9/A9 @ Dunblane
Keir Roundabout -> Doune
Doune -> Deanstoun and on to B8032
B8032 -> A81 and on to Port of Menteith
Port of Menteith -> Aberfoyle
Aberfoyle -> Callander (via the Duke's Pass)
Just after Loch Venachar we turn left (avoiding Callander) -> Invertrossachs
Invertrossachs -> Callander (and head back on the A81 to the earlier junction)
A81 on to B822 (Thornhill)
Thornhill -> Stirling (past Blair Drummond Safari Park)
From Stirling we can either jump on the A9 and head to Glenbervie and then head towards Alva or head out towards the Uni and then along the Hillfoots to Alva.
This is just a suggestion - I've never been to a car meet before and have no real idea what goes on, but I figure if you are in the area you may as well see some of it.
If this isn't what is planned, then let me know and I'll shut up and just look forward to the day.