Can't offer any suggestions on the throttle cable, but ... on the wipers, yeah, I can.

I "rebuilt" both of the wiper assy's on my 91. Once you get the wiper motor off. You have to remove the nuts holding the wiper assy's to the cowling. Once they are out of the truck it's pretty easy to use a brass punch and knock the seized parts loose. A generous spray of P-B Blaster or BG's In-FORCE. Once free and clean, a little light grease and reassemble. Actually, the whole process only took a couple of hours (I know, I know, I'm slow, but I'm old!!!). That was several years ago and things are still working great. Good luck!