Looking for some help on buying a light twin like a navajo, 414 or even a cheyene. I've never bought a plane before and neither has the guy that is actually the buyer, I'll just fly it for him. Speaking of which I haven't flown any of these how are they, solid, good payloads, good range, fuel burn?

What should we watch out for or stay away from?
TT
time since overhaul
wing spars
maintenence nightmares
Avionics(I would be happy with 430/530)

It would be nice to get into something that we don't have to worry to much about and put it to work right away.

Typically how long does the buying process take once you've found the plane you want to buy?

Thanks for any and all help!