The only thing I can say is that you should be sure that it has a side mount radiator. It should also have the hydraulic fan drive.
Cooling the radiator is everything. Even most side mount radiator systems have additional electric fans on the other side of the chassis, blowing air across motor and engine housing to the radiator
I used to have the ISC cummins in a 36 foot Monaco set up as above.
Now I have a 40 foot Monaco with the ISM 500 motor and Allison 4000. What an unbelievable difference. Climbed a really long, very steep grade at 45 MPH with a boat and trailer (about 7000 lbs., rig is another 41,000) Trans saw 175 degrees (highest I've seen it get) motor went to 205 degrees.
Now, those older ISM 500's are cheap, very durable and don't need DEF. They also come with a Jacobs Brake which is everything.