Remember the most important thing is whether you can service what you place.
You can have the best layout in the world with the most streamline spectator flow but if the dumpster truck can’t get to the dumpsters because of rain or soft ground or the catering truck can’t get to the compound for the same reasons, you’re in big trouble.
You need to consider these things during your site planning. If your site has a network of cart paths which can handle the weight of forklifts and heavy trucks then you’re all set. However, if your site doesn’t have the necessary paths you will need to build access roads to the facilities which will need servicing or place them in areas which will have the least amount of damage from bad weather.
I have been on event sites which decided to roll the dice and not build any roads and a storm came through. It was a mess. It took forklifts with chains and tow trucks to pull out the stuck service vehicles.
Then the restoration costs were excessive due to the damage.
You either pay now or pay more later definitely comes into play here. Either put the roads in before the event or pay a premium if you have to put them in during the event as invariably the only time to do if without interfering with the event would be at night, unless the lack of a road becomes necessary for the event to continue, such as a bus loop.
You might work a deal with the venue site to take all the rock you put down to help reduce your costs.
The lack of access roads or compound stability can ruin your event. You need to plan for it.