sounds like a good idea, should get a good amount. might wanna get a male so you can pollinate her and maybe get some seeds, and if she gets a good enough stretch you could probably clone.
mix some water before you head out of town, move the lights a little bit farther away and give them a good water before leaving, show your friend how much the pots weight whenever they're watered and tell him to feel how heavy they are before watering. tell him to shake the water before using it as well, and teach him how to take pH and all that.