I'll be in spots C4Z-36-37-38
I believe you can get into Hershey as a spectator/buyer when ever you want. There are no controlled gates entrance to walk through.
As a vendor, I sent up Tuesday morning and I am one of the first to open for business. There is almost no one there before Tuesday except for the people hauling tractor trailer type set ups.
It would probably be a waste of time and effort to be there before Tuesday, but I've never done it. I'm sure you could walk in to the show before Tuesday.