I would start in Bridge and edit caption and/or ddescription of used images.
In InDesign I would use this information automatically with the Object Export Settings.
Complete all Meta Information in InDesign.
Use correkt language in the paragraph styles.
Not everything can be set up in InDesign.
When the PDF is exported as PDF Interactive (Print is not accessible) you should open the PDF in Acrobat Pro XI and use the Wizard:
Tools Panel > Action Wizzard > Make Accessible
InDesign has a lot of shortcommings to compete this task with InDesign alone. But when you use the Wizzard you will see where information or settings are missing or what also happens are not detected from Acrobat automaticaly.
The only thing the accessibility check told me is that some of my Forms did not have labels. The client wants the doc "accessible" so the Read Out Loud features work, but there is a section where sighted people can fill out a form as well. The form works fine as-is so I didnt bother going in and labeling every form field (although they should all have names anyway since I copy/pasted them so they have names like "Text field 1, Text field 2, etc).
Would the forms labeling cause it to NOT Read Out Loud? That doesnt seem logical, but Im open to any suggestions at this point - I have wasted a LOT of time on this.
As far as photos, etc. I make EVERYTHING in the doc an "artifact" (under Object Export Optionss > Tagged PDF > Apply Tag > Artifact) that I did not want it to read. The Client doesnt want any "Photo of building" verbage or any alternate text - just to simply read the text.
Hi there march67. I know it's about a year since you posted, but I'm having the same issue with "Read to end of Document" stopping after reading only the first page. It's very frustrating as I've followed all the steps in InDesign correctly, over and over, to create an accessible PDF that should work. Did you find a solution?