Depending upon the size of the park, hence the length of the runs:
If the utility meters power to you at 4160V 3 phase...
Route most everything at this voltage. Use fuses as against circuit breakers. Step it down at the last moment with dry type transformers with rain shields. (makes them 3R)
Mount a NEMA3R disco directly to the transformer (37kVA ?)
Multi-tap it to six or fewer load pedestals using the tap rules... And since it's buried and out doors... The tap rules are very forgiving...
Provide 50Amp OCPD at the load side at the pedestals.
Ground and bond the Wye Secondaries at the transformers and provide an additional ground rod/ufer at the pedestals.
Situate the transformers so that they are not eyesores and so that they can't be rammed by the clients.
The Code permits medium voltages to run even shallower than low voltages, so you might save on trench depth.
Aluminum medium voltage conductors will cost less.
When you check out existing work focus on recent stuff and take a note as to which contractor won the bid.
Low voltage distribution normally uses too much pipe and wire. It's the distances that do it in. Any reasonably sized RV park is many hundreds of yards on a side.
BTW, more and smaller transformers will permit the operator to simply shut some down. Idle transformers bleed energy, of course.
The NEMA3R disco at the transformer might even be eliminated if you can engineer it right. You'd use the OCPD at the pedestals to handle transformer faults. Up the line the fuse would provide protection.
4160Y120 dry type transformers are an off-the-shelf item and are no more difficult to hook up than 480Y120 units.
Every transformer manufacturer I've ever known will crank them out in short order. The NEMA3R shields are an add-on, be sure to order them.
You might even get the manufacturer to paint them green for you...
