We don't have a CS, but we do have a Roadtrek 190 with compressor frig, and have looked at the CS systems.
The compressor frig in the CS will be running on 12 volts going down the road. The 12 volts is probably the actual compressor design voltage anyway, as it will almost certainly have a Danfus compressor in it. On shore power it will be running on 110volts. It shouldn't need 12 volts when on AC. The frig will use, probably, about 50-80AH per day.
The specs on the CS have jumped around a little with the propane generator. If I understand them right, if you get the E-trek style 8 battery setup, you can't get the the generator. With the generator you are limited to 4 batteries. Even with 8 batteries, any reasonable amount of air conditioning use is pretty near folly, regardless of what Roadtrek says, and they have backed way, way off their original claims of run time.
The new Sprinters are not the same as an old big truck diesel. They have EGR and DPF systems that will plug from extended idling, per Mercedes Benz, which could severely limit the usefulness of the add on engine generator.
If the e-trek is too small for you, all you gain with the CS is cabinet space, as they are built on the same van.