When I first started my nano I used an aquaclear mini to help clear all the sand and particulates out of the water, I would have left it on but there isn't all that much clearance behind the tank where i have it located on my desk. I would definitely think about using an aquaclear mini for circulation as its mounted behind the tank and you don't need to have some sort of powerhead inside the tank (which I think would be kind of difficult as most are too powerful for a tank that size IMO). Just watch if you are using a sponge filter in it as it will eventually produce nitrates (i just had mine in to clear the water and then took it out and ran the aquaclear with carbon only for a few days.
As for a heater, well I'm not really too sure what you'd do about that. I'm using a 50w heater in my little tank. When I was running one of those Azoo half gallon tanks I used a 7w heater and an ikea dimmer switch set at 50% to keep the tank at the right temperature (the heater didn't have a controller on it). As for when you're away the tank should be pretty much self sufficient, depending on what you put in it you could either decrease the photoperiod on the weekends or set up some sort of "auto" top off. I have a kent aquadoser left over from my early days. It has an IV type drip system that I have throttled back to about a single drip per couple of seconds. I'd much rather do that than have to add water every day, this way I can just add water once a week to the aquadoser and it will do the work for me
