My DRW is a 2010 F450. I haven't had any issues although I'm the second owner. The Carfax was clean and it had minimal work done on it and regular Ford dealer service. It's just over 100K files.
I will say that an F450 is probably not big enough for GVWR for a 4600 lb camper unless you buy a flatbed model. I'm just under GVWR with my 3600 lb dry camper with full gas fluid etc. The brakes and turning radius is great though compared to a F350 or probably any other 3500 model. I get around 9.5-10 depending on how I drive.
I'd probably look into a F550 level truck for a bigger camper like a 4600 lb model. Do pay attention to the gearing as it is impactful to the mileage.
