Odometer fix:
Odometer Blackout Problem Fixed!!! - Ford Truck Enthusiasts Forums
As far as I can tell the pcm uses the rear output shaft speed sensor to determine vehicle speed and if your speedo works so should your odometer. Bad solder joint in the instrument cluster causes it to "light up" intermittently but it still keeps track of miles.
You sound convinced replacing the vehicle speed sensor (generic term) will take care of the issue but I personally feel its a waste of time and money. But this is based on my interpretation of your post.
First thing to check on the cruise control is the cable to the throttle and fuse.
There is self diagnostic feature built in to the cruise control but you must know the sequence of buttons to push along with cranking the ignition key. It may tell you where the fault lies.
If you are interested I may be able to take pic from the ford shop manual and post so you can try the self diagnostics. Too lazy to type all of it myself.