Well I managed to get my duct work cleaned out.
Start with removing the glove box, then remove the two screws holding the resistor pack.
Then remove the two screws holding the box around the AC condensor together. This allows the box to open up far enough to get inside. I used a toothbrush to clean the fins. It wasn't nearly as bad in there as I expected.
Then I removed the blower motor and it too was in really good shape. I had to remove the side trim and a relay thing to gain access to the three screws holding in the blower.
But then I decided to get all carried away and remove the squirrel cage (impeller, fan blades) to service the motor.
That's when things kinda went south and I almost ended up with no wind at all due to breaking the squirrel cage. The rod from the motor was all rusty and didn't want to let the squirrel cage slide off.
Then I removed the dust cap to expose the felt and saturated the felt with oil. I bought this oil for the motor,.. it say's it's for electric motors and sewing machines.
Then I put everything back together and it's all working.
I never did clean the heater core,... I'm not even sure where it is ??? But it was the cooling unit I was most concerned about and the air blows through it first. I thought I'd leave well enough alone and just say good enough.