That dial doesn't seem to help much. Even set on 5 is teeny.
She has about 7 inches from needle to arm, 5 inches from top to bottom- so throat space isn't bad.

I haven't decided if I want to start taking screws out and seeing if I can isolate the stitch length issue or let it go....

Triflow oil and heat - something is full of dried up oil - no point in taking the thing apart

Did you clean under the needle plate and oil the feed dogs down below? You don't oil the feed dogs themselves; see where they connect under the machine and oil the moving bits there.
I agree with Miriam--don't take it apart just yet.

I did. There was some stuff on the feed dogs and under the plate but I cleaned it (and bobbin area) good. It was oiled under the machine pretty well. I wiped it and re-oiled.
It's as if turning the knob doesn't "catch"

Mariam, where should I apply the Triflow and heat?

Get a good little flash light an look up inside the machine at the dial's under side. There should be something that dial is turning on - there might be some dried oil on it - I've had that happen - Try the Triflow in there first - turn the machine a couple directions and then turn the knob. Let it rest in a way that the Triflow will go into that part. I don't use heat unless I have to... You may need to put a blow dryer up the bottom of the machine or just over the knob - if you have any plastic parts you could melt them... be careful. I had one machine took about a month of oiling on occasion and turning and setting. It moves great now. I've had the reverse stuck too. One was a real b**** - come to think of it - same machine... I think I turned that machine every direction you could - I think I took it apart and had problems because the shaft on that knob was turning and the screw wasn't holding - had to flatten out the shaft just a little bit. Some machines have access through the balance wheel hole or the back of the machine - check to see how you can access it before you take anything apart. Patience. Patience. Patience.