Follow up post.
Based on some advice from Cosmo, I decided to install a toggle switch for the trans. I left the dash mounted kickdown switch in place so that I could punch that to temporarily downshift when driving on the highway and going up a big hill. I like the idea of a one-time downshift and then going back into overdrive.
With the toggle switch, I can deactivate the overdrive function without having to push the cable in. It's a pain to push the cable in and out.
I went out for a test drive and it works great. One interesting thing is that with the cable in the overdrive position and the toggle switch turned off, the freewheel function works in all three gears regardless of speed. That is cool for when I get into town and want to disable the overdrive. Its kind of the best of both worlds.
