If it's not clear before you leave then it will be tough and I'm not sure what to tell you other than keep the pump running and have someone add chlorine everyday. If you can keep it covered as well that should help.

If it is clear then I suggest the following steps.
1) Make sure you test values are where you want them.
2) Add 1 quart of Polyquat 60% and wait 48 hours.
3) boost your FC to shock level and cover the pool
4) have someone add a gallon of bleach every other day

That should hold....and that's what I do.