... and the fact that we never actually know the circuit layout for definite until the first lap, pretty much.
First year was the full circuit.
Second year was up the pit lane, right into the paddock, left, up to the Avon bridge, left then right onto the pit entry lane, up to the main circuit, hairpin left, down the starting grid, hairpin left and into the pit exit lane.
Third year was down the pit lane and exit, hairpin right onto the circuit, up the grid, in under the Avon bridge (through a single-track gate with big metal posts both sides!

), round a paddock building, back to the cafe and back into the pit lane.
This year was like the second year, but some people in the paddock took about 12 hours to load two ferraris and a tent into the back of a lorry, so the paddock bit was removed and we went straight up the pit lane.
So depending on layout, a team in a Quest or similar could walk all over the field - or not!
Cant remember the vehicle rules, either - many of them were lifted from the pedal car spec (with permission), although clearly not all of them! So you'd need to check about maximum lengths and the like.
All that said, the main thing the event is lacking is more entries, so some BHPC representation would be great - and the BHPC might be more successful than the BPCC has been in terms of getting some of the teams to race more events, purely on the basis of numbers of wheels on existing machinery.