2004 motorhome??

I'm looking to purchase a 2004 Monaco 36' diesel pusher with a 300 hp ISB Cummins motor.
I am a mechanic and I fix 90% of everything that has gon wrong with my truck. .
That being a
Said this motor has some oil in the degas bottle, and at idle you can see slight white smoke. The owner also said the coach was running at 215 then the fan comes on and it goes down only to repeat.
The coach is there top of the line 45,000 miles all options and 4 slide outs in extremely clean condition. The coach is currently worth 50 to 60k and I can buy it for $25k.
I haven't done a exhaust gass test but I'm thinking the oil cooler for the oil in the degass bottle, and the egr cooler for the white smoke... school me if I'm wrong .
The other problem is getting to the motor I will need to take out the rear closet,washer and dryer,bed and storage base and floor over motor .
Whats your thoughts