Any signs of abuse mechanically you can recommend that are common for these trucks ?

 

Buying any old vehicle, make sure you check to see if all the small stuff works like the heater, heater fan, AC, radio, cassette player, power windows, power door locks, and any thing else you can think of. An older vehicle may have some of these that are not working.
I don't think Ford trucks have any serious factory design problems except for the older V6's. Just check everything so you know what you may need to repair and go for it.

 

Thanks for the input.