Since it is still cool and your pool temps are probably not very warm yet, I'd probably do 4-6 hours on the timer. Do you have somebody that can come by and dump in a bottle of bleach for you after a couple of days while you are gone?

Do you still have visible algae? Run another set of numbers. When are you leaving? If it were my pool, I think I'd shock the pool right before I left and then maybe leave some trichlor in there for residual. Or, just leave the trichlor out and let a neighbor come by and pour a bottle of bleach in there mid-week. Make sure they know to do it while the pump is running.