Hey @Gregg_Stebben !
Im a teacher and used Coda forms extensively in my teaching this past year. I ran into this problem often as I had students who worked very slowly and would not finish their form questions in time (often times reading comprehension questions)
What I would tell them to do is press submit, no matter how far into the form they were. Then directly below the form I had the form results but it was only showing one cell, and I took away the column headers and the lines, and I used a filter formula to ensure that each user of the doc only saw their row (First question in each form asked for name, aka the person filling out the form selected themselves in a people column)
The one cell that was showing was a button that said “edit my answer” and used the Activate(thisrow) formula.
It would then pull up in detail mode their entire answers (just ensure that you use the same layout on that detail as the form itself)
This, from a user perspective, “saved” their answers right where they were at in the form and allowed them to continue working on the form as before! Hopefully that helps. Happy to provide example doc if my rambling doesnt quite cut it.