On the Woodlands campsite on Grand prix weekends it usually works like this:-
The site is subdivided into lively and family (quiet) areas, also each area has an electric hookup area at extra cost.
When you arrive you are directed to your chosen area, is is marked out into individual pitches in lines.
You are instructed to go to the next available pitch in the next available line, where a marshall will line you up within your pitch.
In the past I have said to the marshall "my mates coming along later can I save the next pitch for him?"
They have always obliged, how they would react to someone saying " can we start a new row and save it for all the Westy owners" i dont know.
But if you fire up the BBQ quick and offer them a burger and a can of beer, I'm sure they would be happy to please you iyswim.
There are bars, food stalls and plenty of good clean toilets and showers available on GP weekends, as the Classic is only 2 weeks after the GP I imagine they will all still be in place.
Woodlands is situated behind Vale grandstand, between Stowe and Club, about a 10 - 15 minute walk into the circuit depending on where you are on the campsite (it's big)
I hope I've covered everything there. HTH
Woodlands campsite from Club grandstand.