If all the sites are set up to face door to door it is time to find another park. That is just poor construction of a park. I wonder if it was actually built to be that way or if someone just decided to allow people to park any way they dang well please in each site and you just ended up with that situation because the people with the party decided parking in the site backwards would give them more room, the heck with everyone else.
If that was the case, it illustrates why we are very firm in how we allow people to park in sites. We get people from time to time who want to park in sites backward. They think it gets them a better view, or makes it easier to get into or out of, or allows them to share the yard with their traveling companions, or maybe they just are rebels and want to go against the grain. We always say "NO" for the very reason the OP endured. Even with people traveling together, we don't allow it because once you let one rig do something, other rigs are sure to follow.
As for numbers on the site, it is pretty easy have and enforce rules about occupancy per site, but impossible to have or enforce a rule about how many people can be on the site at one time since there are often multiple rigs traveling together and they are traveling that way exactly because they want to spend their campground time together. However, party with 30 people in a single RV site should have been moved to a more appropriate location than that single site and if such an area was not available the party should have been shut down by management as not being appropriate for the facilities.
The OP's issues are a result of either poor park design or poor park management, period.