Go to the wrecking yard and source the parts from similar truck/car. Or ask on here. Stay away from the early transducer style (uses speedometer cable to drive a box in the engine bay) the later speedometer VSS-driven cruise (at least '83-86) is superior IMO.
Cars would be run pretty much the same way, but I understand, not a ton of 80's rigs left in most wrecking yards. But all in all it's a pretty easy retrofit IMO, the entire system is separate of the main wiring harness, so it's just a matter of adding/swapping, and providing power and ground.
I've probably got SOME of the components around to do the conversion, but now that I think about it, most of the parts are going to be the same up until 1991 in this bodystyle, and they may have stayed similar to 1995 since TBI was still being used.
The S10's (and probably cars, later trucks) went with an electrically driven motor to control cruise, instead of the earlier vacuum, and they use the same mechanisms to control it as the vacuum...so some mix and matching is possible.
Buddy wanted to put cruise in his 1995 K2500, managed to find a quite old "NOS" aftermarket cruise setup that had you strap some magnetic piece to the driveshaft, etc. It actually works, but I'm not a fan of the exposed components, which I managed to dismantle driving over light brush.