1) Nice place to park i.e sea front
2) Public loos open 24 hours or first thing in the morning ( yes, I am female)
3) Free parking or cheap parking
4) Space to get cooker/table/chairs out if weather allows
5) Quiet enough to sleep soundly at night
6) Bushes/trees/beach in the absence of public loos
7) Nice town/pubs to go into at night

It is an advantage having a tin top as I dont think people know we are sleeping the night.
Early Spring, late Autumn and Winter stops are great as lots of places ( tourist areas and seaside) don't charge for parking after 6.00pm.