Hi Paul,
I agree with everything the last two respondants said- the Toyota 7FGCU15 is a terrific truck, but NOT suited for running in gravel. In case you don't know, changing the tires to pneumatic on this frame is not possible- a pneumatic truck frame has not only a higher ground clearance, but also the counterweight is moved rearward for improved counterbalance and stability on a yard surface. What you would need to look for is the pneumatic version of that unit; a 7FGU15- same set-up, look, engine, etc...but made for what you do. Your local Toyota dealer should have a trained professional that could look at your application and recommend a nice "certified used" Toyota unit that comes with an excellent factory warranty.