I also strongly reccommend visiting handy bob's page and reading the RV battery charging puzzle.
for a basic understanding. I also second Piersg's recommendations, I would suggest the same links.
I'm no expert and I'm still working on my system myself but I will try and break down for you a rough checklist. First you need to establish your wattage needs, an AC will take a lot of wattage, as will hair dryers, induction stoves, space heaters, (things that mess with temperature) so all of these would be good to avoid if possible. It's also worth noting that if AC is very important to you, then you should take insulation very seriously assuming you are concerned about the long term game plan. That said I decided on about 1000watts, which is convenient because I have a nice 1000watt honda generator I impulse bought with my tax returns
. My big needs are my rice cooker which is rated at about 1000watts, and my wifes hair dryer which is rated at about 1200watts. Both of these are a bit of a gamble, but I am assuming that the hair dryer on low will be below 1000watts, and the rice cooker will be below 1000watts when it's not cooking.
INVERTER: You need this to turn your 12VDC battery electricity to 120VAC. For my 1000watt needs, I will be using a magnum mms1012 pure sine wave inverter charger. This is probably a little expensive/excessive, but since I'm not an electrician I figure reducing parts is good. You can save a lot of money by buying a modified sine wave charger instead of a pure sinewave, but it seems that it's in general better for your devices to use a pure sinewave charger.
CONVERTER/BATTERY CHARGER: If you do not get a inverter charger like myself, it's within your best interest to get a device that will turn AC wall power into 12VDC to charge your batteries.
POWER SOURCE: Whether you go with a generator, solar panels, wind charger or all of them, that's up to you. However you will want to make sure you have enough power to sustain your electrical needs.
BATTERIES: Flooded "golf cart" batteries, seem to be the cost effective solution, make sure to keep them in a well ventalated area because they release hydrogen gas that is explosive.
CHARGE CONTROLLER: This is necessary if your chargers do not regulate their charge, your batteries will probably have special charging needs and this will protect/aid them in keeping a long life, also it will be necessary for solar panel charging. I will be using the trimetric sc2030
BATTERY MONITOR: You'll want to have this so you can see how much juice your batteries have in them. The trimetric 2030 is what I will be using.
BREAKER PANEL & SUB PANEL: This will middleman between your power source and your battery charger, it will protect your electrical system from overcurrent. My conceptual knowledge kind of tapers off around here but I believe you will want a sub panel to divide your electrical distribution: A dedicated switch for your AC, a switch for your kitchen, a switch for your bedroom/living room, a switch for a dryer in the bathroom, maybe a switch for using tools outside?
you should also consider a water cooler this diy swamp cooler
which will be a considerably lighter load on your electricity
In case I didn't clarify my credibility: I have no certifications, no professional work experience in carpentry/tradesmen skills, and do not have electricity installed in my bus yet. There are a lot of people on this forum who I would trust over my word, however maybe my ramble can help you find some direction.