I'd give you my thoughts on this (as that's how I get to the track almost exclusively), but I'm guessing that your vans are substantially different than what you get over there.
That said, here's a cultural universal: The chock. I use Baxleys (and there are a lot of knock-offs); not only does it lock-in the front wheel handsomely, it also adds a great deal of stability to the bike in the van, trailer, truck bed, whatever. Allows for minimum of tie downs (only 2/bike, depending on the attach points you have available and assuming there's doors or a gate behind the bike), and with a minimum of tension on the tie-downs (don't have to totally lock down the suspension). If you don't use tyres warmer, more convenient to use than traditional stands trackside, if you bike doesn't have a sidestand. Only downside, is if you roll into the chock with hot race tyres, they tend to stick in the chock sometimes better than one might prefer.
For the bars, I use these (of which there also a number of knock-offs):
http://www.cyclecynch.com/CCpages/CCproduct.html . Quick and easy on/off.