I have a 5 gallon bucket with an IV drip to drip in top off water. That will last me about 4-5 days. As far as heat, I can't help you there. I live in Alaska. It's not a problem here. As far as general maintenance here is the trick. The more you plan, and the slower you take it the easier it will be. This mainly comes down to get the correct equipment the first time around. DON'T SKIMP!!! you will regret it later, and end up spending more money to correct the problem then you would have originally. I spend 5-15mins a day feeding my tank and looking everything over, and then about 2 hours on saturday doing water changes, and misc other things (mainly looking at the tank). and that is it.. If I really wanted to I could take a week long vacation and be fine. My tank is balenced enough to substain itself for a week. I would only need some one to come over every other day to feed my fish (which I pre-package each feeding for them so they cant screw it up!).
I hope this helps some..