dwh
Tail-End Charlie
Aye, available in 12/2 and 14/2 as well, and it's got a pretty tough insulation with good UV resistance. Most of it has a ridge on one strand to ID the positive, but some doesn't. I'd make sure I got the stuff with the ridge.
Been a while since I compared, but it seems to me that last time I looked, landscape lighting cord wasn't really very cheap.
To the OP:
#6 is overkill. But...overkill is a good thing when it comes to low-voltage DC wiring.
With #6 to the fuse block, #12 to the accessory plugs will be more than adequate. It will be fine for the fridge as well for a short (say, under 10') run.
And you can't go wrong using marine grade gear.