We had a bad experience on our Harley. My wife wouldn't get back on it. So, we sold our Harley and bought a 1966 Coupe. It was taken down to bare metal and repainted. It came from the dealer with factory A/C and a front bench seat. It's currently being readied for spring. The horn doesn't work yet nor does the A/C. We're going to find someone to repair the seat. We took it out to replace the tracks. I'm going to refurbish the originals as they are different from normal seat tracks.
I'd like to replace the wiper motor and linkage because it has one speed. Slow. The way the wipers move tells me they need new bushings. However, seeing what needs to be removed first has me less than anxious to do it. I may just RainX the windshield and not drive it if it looks like rain.
Recently I was in the same position as you, I opted to replace the A/C with a Classic Air set-up, I figured I will pay now, or later, it works great. I live in Florida so it was a no brainer. (two day project for a 68 year old man in his garage). But you will need access to a vacuum pump and gas to charge it up.
My wiper motor was also not working. I found that there is only one aftermarket vendor that sells a replacement for the motor, I searched for days online, but you also have to change the switch to accommodate their wiring/motor. Or I believe you can have yours rebuilt. (let me know if you need the name of the vendor that sells a replacement) And yes it is a ball buster to remove. I removed the steering wheel and dash instrument cluster, which is needed to reach in and remove the arms clips. It is a tough job but do-able. Plan on taking your time. I also removed the front drivers seat (Easy, two minutes) and put two pillows on the floor, this allowed me to lay on my back and get under the dash comfortably. The seller of my car told me he was nervous to tackle the wiper issue, that just made me feel better after I accomplished it. I did end up with a few scratches on my arms, but it was worth it. Nothing ever goes as easy or as planned so I just take my time and when I get frustrated I take a nap..
Best of luck to you.
I'm finally back in the Mustang forums. I had to take off a few months in order to build my brother a flintlock rifle for Christmas. Then I began a total reorganization of my garage. Later this month i'm going to get back to my 66 and put disc brakes on her.