Welcome to TDR land Street!
Bought Black Sheep in June of 2004 with 239,000 on the clock. The two PO's had used it for delivering campers all over the U. S. just as I have done.
At 800,000 everything that is replaced could be considered "normal" maintenance costs! Well, almost. It is easier to tell you that the basic engine is the same minus a head gasket replaced at 575,000 miles. The current head gasket leaks again and needs replaced but I also believe the head is damaged and needs replaced, too much heavy towing with Smarty on SW #1. Every mechanical item has been replaced except for the brake master cylinder, ABS pump, windshield wiper and heater motor. The most trouble time and $$ wise was in 2007 when the NV5600 was replaced 3 times, twice because other circumstances shocked the drive train which broke 3 teeth off of 6th gear at the root the first time and broke a brand new main shaft the 2nd time. The 3rd replacement was because the rear output bearing got hot which fried everything in the transmission, blamed on a design fault (yeah, it got the reman people out from under warranty). Overfilling with a total of 6. 5 qts of Royal Purple has helped the current one last 238,000 miles
As far as tires I get 180,000 miles out of a set by rotating them every 6,000 miles and keeping pressures in check.
The rear brake shoes lasted til 665,000 miles and the rivets were just getting into the drums when I had the rear end rebuilt (everything was new except the axle housing and axles!). The drums didn't even need turned and the wheel cylinders are still original! Just new shoes and spring kit. The exhaust brake helped make that happen.
I have always worked toward getting Black Sheep to 1,000,000 miles and it still may happen. Currently am considering a medium duty truck to haul one camper and tow another behind it which pays considerably more $$. Time will tell...
Godspeed,
Trent