How do I wire my trailer for generator power

[H.A.]

You might as well build your trailer with 30amp service. Put your heavy appliances on separate circuits.
If your RV park provides it. Might as well run air-con, microwave, coffee maker etc at will.
If plugged in on 'genny, just realise you wont have capacity to run as many things at once.

Btw, the few RV parks I seen have 20 & 30amp receptacles. If the park you attend have only 15-20 amp receptacles, you would need a simple adaptor that converts your 30amp 'shorecable' to fit a 15-20amp receptacle.
There is a good chance you will need this adaptor anyway unless your 'genny is fitted with the correct 30amp receptacle.