The 1947 - Present Chevrolet & GMC Truck Message Board Network

Get a Rostra kit if you want to have most if not all of the pieces to install cruise control easily. The brackets looked a little ghetto on the units I saw back in the 90's and the pictures on Summit don't look much better. Fabbing your own is part of the adventure. Dakota Digital sells turnsignal stalks with cruise control switches so you may want to look into one of those rather than the cheap aftermarket looking cruise switches that come with the Rostra kits.

You can piece together a setup based on the ElectroMotor cruise boxes that GM used on the T400 & 4th gen F-Bodies that's essentially the same animal as the Rostra units. It's a scavenger hunt but it's mostly GM parts and can come in at a fairly inexpensive price point.
It should look reasonably close to a stock GM installation when you're done... If:

You carefully choose component placement and build decent brackets where needed.
Avoid the ghetto butt splice and bare wire nightmare i see so often.
[**]Use Crosslink Poly wire (SXL, GXL, TXL) in the proper gauge.
[**]Insert the wires in split poly or expanding mesh loom and tie them up keeping in mind there should be droops to allow for body to frame and body to engine and engine to frame movement.
[**]Use grommets to penetrate the firewall.
[**]Use drip loops at the terminations and firewall penetration to route water away from these locations.
[**]Use the original Metripak, Packard, and Weatherpak connectors by extracting the original terminals and inserting the new full length wire with a fresh terminal and seal properly crimped on the end of the harness wires.
[**]Insert the proper empty cavity plugs in the empty connector holes to prevent water and salt from gaining entry and screwing up the module. Clipped off wires will not protect the connection because water will creep in.

You could also install the 1968-1982 transducer setup that GM called CruiseMaster. If you go this route you'll need to install new vacuum lines, a new vacuum throttle dashpot, and likely replace the vacuum valve on the brake pedal.

Dakota Digital sells replacement cruise control turnsignal stalks that look reasonably stock. You may want to look into one of these for whatever cruise setup you install.