In our previous, much smaller rig, we didn't use a trash can.
I put one of these on the side of the kitchen cabinet:
https://www.amazon.com/Camco-43593-P.../dp/B000EDOT7I
Now granted, those grocery bags aren't very large - but we found they did just fine as long as you make sure they aren't torn.
These back holders work great, don't take any room - and come in two packs - we had one on the outside of the trailer and one inside.
Just remember to take the outside bag down at dark or you may have 'visitors' during the night.
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Buddy Ray - Atlanta
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Jayco 2016 Eagle HT 26.5RLS
Ford 2016 F150 Lariat, 3.5L V6 Ecoboost
Max Tow Pkg, 36gal tank
Reese Sidewinder and Reese Titan 16k hitch