I am in the process of replacing my Dometic RM1350 with a Samsung Residential.
You'll have to find out the dimensions of the opening and then find a
residential to fit.
I found two to fit my opening
1) Samsung RT21M6213SR/AA
2) Samsung RT18M6213SR/AA
They are 21 & 18 Cu. ft. Counter depth.
You can find dimensions on Samsungs web site.
I also went with 2 6v deep cycle batteries and a Xantrex Freedom XI 1000 pure sine wave inverter.
Good luck in your project.
C.B.