With SuiteQL has anyone found that certain fields (like Document) on a custom record do not return in a SuiteQL query? They are also not visible in the Records Catalog either. Is there some way outside of creating a text field and copying the data over that I can do to make this data visible in my query results?

For document type fields, what I usually do is if I need to do some operations on the file is I create a field which saves the file internal id in it And query the new field to get the file internal Id. And do whatever I want in the script by loading that file. If you need the file data not the file, then storing that data on a long test field might also work.