Tanks are expensive to run in grow rooms, they will cost you about 50-80 bucks a week to 10 day's. It could last 2 weeks if you are lucky but to fill the big tanks are expensive and you don't have a truck. You are better off with a generator then you only need to buy propane or you can just use natural gas if you get that version of generator.

I'll see what I can dig up and write something up for you and the others. It may need to wait until the house is on the market so I have more time though.