Very Slow Typing

Question

I have a document where every character typed takes 1 second to display. This makes typing almost impossible. I haven't been able to figure this one out. I am actually getting ready to start a new document using this one as a template. Here are some of the details and what I have tried:
Single document 30 pages long
There are many internal cross references, but no external cross references
Small TOC
Most paragraph styles are 2-column. Headings are 1-column (text frame is single column)
A lot of graphics, 3 to 4 per page. Inserted in-line on their own text line.
Original problem didn't happen until the original document was 80% complete.
Things I have tried:
Exported/imported as IDML
Changed styles to be single column and set text frame to 2-column
Break text flow at major headings (new page)
Wiped out the whole document and copy/paste back in as unformatted text
Because I am creating a new manual based on this manual, I have deleted most of the original text and graphics. It is down to 10 pages now, but the problem still exists.

Answer 1

RTS: Actually, the way my cookbook is designed, it reflows pretty much every time I make a change. I don't have one recipe per page, but instead have them in a fairly compact format--several recipes per page, much like the Fanny Farmer cookbook. The book has 30 or so chapters (about 300 pages). It has cross-references (I restored them after deleting them didn't help) and it is not fully indexed but part-way there (I am a professional indexer, so I can index my own work).
Joel:  I am in the process of trying PeterHol's suggestion.  I am converting all my text frames to single column and turning column spanning off in all paragraph styles throughout the book. I tried changing the styles in one chapter and then synchronizing with the other chapters, but InDesign crashed. I tried synchronizing just a few chapters at a time. ID crashed. I tried synchronizing just one chapter at a time. Crash. After some experimentation, it seems that the changes need to be done in this order to avoid ID crashing:
Change the text frames to one column instead of two.
Import the non-span paragraph styles. (After I change the text frames, I still can't synchronize--ID still crashes, even on one chapter.)
Unfortunately, my basic text frame object style isn't working the way I would expect it to, so I have to change the text frames manually page by page. I would expect to be able to redefine the text frame object style to just be one column and then have all the frames update, but that isn't working. Instead, all the frames then show that they have the basic text frame style, but with an override, and I don't know how to make it so that the new style applies to all of them in one operation. Right-clicking on the object style (with one text frame selected) and choosing "Apply style, clear overrides" isn't working. Neither are any of the other choices for applying the style. No matter what, the frame still has two columns, even though the style is now defined as one column.
So now I am going through each chapter one at a time, page by page, changing the text frame object style, then changing each frame manually (fortunately, that's pretty fast: select frame, press Ctrl-B, type the number 1 [because the number of columns is automatically selected], press Enter, go to next page, repeat). After that, I import the non-span paragraph styles.
I actually don't mind this process because I may redo my style entirely, and it's been a while since I have gone through my entire book, so it is nice to see what it looks like while letting my creative mind work on a new design.
If I still have the slow problem after this process, after I cry a bit, I might share the files.
Edit: Not sure why I thought it was 30 chapters. It is 16 chapters, a bit under 300 pages. Unfortunately, I got to a certain point and now I cannot open any files--ID crashes as soon as I try to open either a chapter or the book file.