Shift linkage, won't shut off in 'Park'
 

I have a '93 K Blazer and the other day I started it up and it wouldn't come out of Park. After a bit of "finesse", I got it out of Park and drove home. The key would not turn to the 'off' position. One of my friends mentioned that the shift linkage might need to be adjusted. Is this correct or is there something else that could be the problem? If he is correct, what is the best way to adjust the linkage? I used to be a mechanic and can still work on vehicles but I haven't had any experience with this type of problem with this old of a vehicle.