There isn't a ton of model specific stuff to watch out for, the big ticket items are corrosion, engine condition, avionics, etc. that apply to any plane.
The only C model stuff I can think of are landing gear disc condition, leaky wet wing, whether or not the original PC wing leveler is still installed and if so then it's condition, and the potential for a recurring 100 hour eddy current inspection on the prop.
None of those are anything like a "deal breaker", just the only Mooney/Ranger specific things I can think of.