Hmm.. Fluttershy being my personal favorite, my initial instincts tell me to spend as much time as realistically possible with her. But I suppose my action would be simple: Visit each of the Mane Six, and explore and socialize as much as I can before I'm whisked back to reality.
Tea with Fluttershy Atttend Octavia recital Visit Ponyville library Have pleasant chat with Twilight, Celestia and/or Luna Sample famous Apple family Cider Have a snack at the Cakes' bakery (forgot what's it called :/) Not necessarily in this order.