My DS did STP in summer 2015 . . . here is his remembrance and advice:
Typical day . . . wake up early (~0600) . . . do organized group PT (0630) . . . breakfast (0730) . . . then class (0800) until lunch (1200) . . . then more class after lunch until 1500 . . . then intramural sport activity after class . . . then dinner (1830) . . . evening for doing homework and making friends.
Take aways: Get to know your future BRs, Learn where things are on Post, Realize upperclassmen will be observing you, You are not yet in the "Rat Line" but be respectful to upperclassmen there for summer term
Things to pack: Polo shirts, shorts, couple of pair of athletic clothes to tide you over until they issue "gym dyke", socks, running shoes . . . they will issue combat boots and low quarters (black dress uniform shoes -- don't pre-shine the shoes -- you will be taught how to shine your shoes during Hell Week -- if you already have shined shoes during Hell Week, then you will get to do extra PT while others are learning to shine their shoes. )
How to have fun: Enjoy 4th of July festivities, Walk around and get to know Lexington (it is a neat small town), Do the VMI offered activities and field trips, Tube in the Maury River . . .