Well, if you use standard truck tires on it, you'll get 30-80,000 miles from them. They'll dry rot before they loose all of the tread. on a 5-1/2 gal oil system, that is tested for bad oil every 3,000 miles and sometimes changed as far out as 30,000 with constant use.
Other than that, unless you restore it or drive the heck out of it, there shouldn't be too much upkeep besides batteries, tire pressure, and the occasional wirebrush and paint.
As far as a first car / truck, not a great idea. You should get a class A with airbrakes endorsement to learn all about how to properly operate and maintain the heavy trucks, but it is not required in most places by law, which is really a safety issue, but they base classes of drivers licenses on gross weight of the vehicle.
I noticed today driving with Jim (who is very good for a first-timer on a deuce) that it is VERY helpful to have some OTR background (we used to own a freight brokerage, and drive a few weeks a year) or at least some time in the cab in all 4 seasons with an instructor. There are major differences between a deuce and a car. Air over hydraulic brakes, careful monitoring of the tach, using brakes to slow instead of shifting, rpm matching / windowing, braking distances, reaction skills (steer-countersteer), pre-trip and post-trip inspections... just a couple of items.