The only specific time is that the Gates open for Vendors at 6am on Saturday. Vendors leave when they want. Some stay overnight for Sundays.
If you are a shopper we suggest coming before Noon either day. Saturday is the biggest of the two days. Sunday is slower and more laid back and only lasts until 12pm or 1 pm.
Gates stay open from Saturday through Sunday when the gates are closed at 3pm. People and vendors are allowed to camp overnight. Vendors are more inclined to stay if there is shoppers and good weather