Concerning the laws, cf. the town planning code.
Otherwise, I can offer my land at any time of the year.
The minimum necessary equipment is a large and nice garden to welcome my campers, but to attract more guests, I should provide other small things like breakfast or even loan equipment ;-)
In general, the hosts provide :
Dry toilets and solar showers OR access to the toilets and bathroom in the house
Access to drinking water
Access to electricity