Big panels get the job done. Some of the best most accessible panel sets are available now from Harbor Freight in the $150 to $200 range. Their 45 watt kits can be set up in tandem to increase power, so running three sets on a 7 amp charge controller with a 2000 watt inverter on any decent deep cycle battery or a few old car batteries rigged up in parallel gives you ample power to keep everything running and operate the occasional power tool.

Warehouse equipment battery packs give you the best bang for the buck, as they are often reconditioned and are in big heavy packs which can hold a whole lot of juice and usually have built in charging units and charge controllers. You rig a few sets of the panels to the system AND a small generator, and what you get is a system that will maintain a decent size little retreat quite well when you are not there, then when you arrive you will be using more power, but run the generator when needed as needed to bring the battery bank up, for example when you are using power tools or heavier equipment.

Just to let you know the numbers, the forklift battery packs run $350 to $450 when reconditioned, and that is in fairly big steel housings (two to four man lift), and will run a small cabin for a long time. A single good quality deep cycle battery will be $250 to $350 and will run down quickly if you are trying to use it with power tools. Such batteries are rarely available used or reconditioned.

The big battery packs can be recharged any number of ways, not to include just a vehicle running at idle. quietness and fuel consumption on a Geo metro at a moderate idle while sitting in neutral with a jumper line running out from under some plug-ins under the hood is not half bad compared to running a loud and smoky 5000 watt generator.