You will get enough about tires from others. i wanted to tell you I really like working on the Astro,things never got complicated and out of hand,they did have some problem areas.
Window motors were very prone to failure,AC compressors leak at the housing halves(this type of compressor is used on many GM cars) if you car has rear AC and most do the line that carries the charge to the rear (GM knows it by the name"muffler hose") likes to rub on a sharp edge of the left rear part of the engine block,causing a fracture in the line.
Some HVAC problems that are usually related to vacuum source or the control head its self.
Sliding door gave some problems,easy adjustments were the fix.
Overall not a bad Van to work on, I have see repeated ring and pinion replacement when the vehicle is used to tow at its max rating 5000lbs.
The only car I ever saw with two idler arms,alignment tech must be a good one.
I even put rear audio in a Astro that did not have it factory installed,a bigger job than you would think.