This cracks me up. At this point the tuning software is free for these things. It only takes a $60 tool to be able to do almost anything you want to it. I get the desire to want to simplify it, but the complexity of properly hacking and splicing into the stock harness without causing yourself even more problems is not insubstantial.
My thought, if you end up doing this, would be to get an Edelbrock RPM Air gap intake and the carb of your choice. Get yourself a basic HEI and a TPS for the carb. When you change the cam, pull the 4x reluctor off the crank and replace with a double roller timing set. Keep the majority of the harness and stuff intact. Splice into the tach wire to the ECU with the tach signal from the HEI. Run the TPS sensor on the carb to the TPS wires into the ECU. Adapt the cruise control cable wire to the carb, and you are done. All of your gauges should still work. Cruise control should still work. Trans should shift like stock.
You'll end up spending just as much to buy needles and jets to tune the carb as you would have on the tool to be able to tune your stock vehicle. You'll be spending about 4x as much just to convert the engine to carb... but whatever.