Everyone seems to find 1000 watts works fine with a residential fridge. Surge rating is typically double the rating. Two batteries should be fine as a buffer to roll down the road. Camping off-grid you will want 4+ batteries and 500+ watts solar.
I have and recommend GoPower brand inverters. Yes they cost a bit more. I only recommend sine wave.
GoPower 1000 watts $425 Shop around
KISAE TS15A 15A Automatic Transfer Switch $50For custom made 12 volt wire I get mine made here:
http://www.genuinedealz.com/custom-cablesVery good price for premium wire with the proper lugs crimped on and sealed with heat shrink.