Gone Truck'n,
I too have an '89 Tioga on a Ford E-350.
I can tell you that your new-to-you Tioga is a great first time RV. You will learn a LOT about RV's. Being that the "coach" was build by Fleetwood, most parts are common and still available. The same goes for the Ford parts also.
Mine also has the 460 motor. That thing is huge and HOT. And with the 3 speed trans, your gonna what to be light on the gas pedal. Typical driving speed for me is 55 to 60 mph. ( around 3400 rpm. Pretty fast for a big motor.) Otherwise you can watch the gas gauge move! I have towed a 12 ft. loaded trailer. Didn't make any difference in mpg. Here is a link to a CD which helped with the motor and Frame:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Because the leaf springs are 30 yrs. old, they sag. I installed the Firestone Ride Rite air bag suspension kit and that made the handling so much more better. I would highly recommend this being one of your first add-ons. Really improves the ride. Here is a link for the kit I purchased:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Now that the winter weather is here, yes you HAVE TO winterize you water systems. First... Get the water out! there are drain valves near the hot water tank, and under the shower. Drain the hot water tank. Then se an air fitting on the city water inlet and open all of the faucets, and shower valves, also the toilet. Then pour some RV anti freeze down each drain. at least enough to fill the goose neck trap. <<<<< Don't ask me how I found this out. Again this is a great RV to learn on.
Bill K
In the next post I'll attempt to attach the 1989 Tioga Owners Manual.