I've done several Parks like this. Theresa lot more to them then you think. Voltage drop is a Big factor for one thing.
Lotta the Manfactors that supply Equipment for theses have software programs that well do all the calculations for you. JUST make sure you read 551 completely.
The last one I did they wanted 80% of sites rated for 50 amp plugs due to the larger RV's nowadays.
Yoopersup