Honestly? The best thing to do... is try and make sure you don't have to leave the plants by themselves for that long to begin with.
I understand thing happen in life.. where we have no choice but to go attend to them. However, if that's not the case here.. then you should have thought about this way before you started your grow.
I don't know what to tell ya. IMO, I think they'll be fine.. if its just two days. If your coming back in just two days.. just make sure the plants have been watered.. and double check your light timers and make sure they're in good working order.. and correctly set.. and you and your plants will be just fine.
peace.