AC Inverter Install

2006 Tundra SR5 V6, looking to install an inverter.
I have a few inverters of varying amperage that I've plugged into the cigarette lighter, but I'm looking for more amperage than that outlet will provide. I'd like to hard-wire one of the inverters in the cab, or in my truck box in the bed.
I don't want to just "tap into" an existing wire, so I'm wondering:

1. Is there an existing but unused harness I can tap into - maybe an accessory I don't have (mine is pretty basic SR5, no frills like power seats, etc)?
2. If there isn't an existing harness to tap into, can I wire it straight to the fuse box under the hood, installing a fuse in one of the unused spots, etc?
3. Is this something that is more trouble than it's worth, and maybe the easier path is to just hook inverter wires to the battery? I'd like to have some slick installation, but if too much trouble (or dangerous!), I'll settle for the old-school method

Thanks for any input - and if this thread already exists, kindly point me to it, and I'll go there.