If possible, choose a "counter depth" or "cabinet depth" (the terms are interchangeable) residential fridge. Those tend to be pricey, though. You still have to pay attention to height and space for the door to swing open and/or drawer to pull out. Some floor plans may have limited space in front of the fridge (e.g. a cabinet directly across from it).
Yes, you gain some 6-8 inches because the RV fridge has a wide space behind it. Depending on the fridge design you may be able to use nearly all of that space. As long as the new fridge does not have cooling fins on the back (most modern fridges do not), it can go quite close to the sidewall, maybe just an inch or so gap. Modern fridges generally draw air underneath, then up the back and out over the top. You need to allow space for that, as well as venting for th air to enter/exit.
Alternatively, an apartment size top freezer model will usually fit and be inexpensive. I installed a GE 14.4 cu ft model and it only stuck out about 2" more than the Norcold. If I had another 1" of space for the door to swing out, I could have used a 16 cu ft model. However, the 14.4 was still 20% large than the old Norcold 1200 and much more effective as a fridge, not to mention frost-free!
The trick is to carefully measure your opening and door swing space and then compare to the fridge specs. Fridge makers provide very detailed dimensions on their websites, including door swing, sizes with and without handles, with or without the door, etc. The "without door" size is critical in determining if the fridge can be brought through the RV door vs removing a window or windshield to get it inside.