You might get better suggestions if you provide the maximum towing capacity of your Avalanche. If you have one with the 8K towing capacity, you may be able to find a lightweight bunkhouse model that would work. So, I'd provide more info about your truck so you can get some realistic suggestions.
2012 Newmar Bay Star 3302
Blue Ox Avail
BrakeBuddy Advantage
2015 Malibu
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Andy Dufresne, The Shawshank Redemption