It all depends on how much inconvenience you are willing to deal with.
In your shoes I would get a LARGE propane tank (I think there are 100 gallons available) to run generator and cooking and heat.
You could get a pump out service and haul in water.
But you must have enough driveway available to get the trailer, propane, water, and pump out service in.
Looks like the first order of business is to get a perc test, and decide on a house location. That will have to be done before you site the driveway. Get the driveway in next. After that, you should be able to get a temporary meter pretty quickly. That will reduce your generator/propane needs.
Find a shady spot. That will help.