I got some answers on the mailing list, and will post them here for posterity...

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For a few files I use often, the best solution was to paste in an exact filename match in the catalog file's < mode > tag, using pipes to separate multiples, if needed. (Thanks to Dale for this)

FILE_NAME_GLOB="dailyActions.txt"

This would automatically apply my custom mode to that particular text file. It overrides the wildcard "*.txt" mode because I specified the exact file name with no wildcards. The order of operations is shown below.

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For lots of files that I don't use as often, I created a macro and put it in my right-click menu (or you could put it in your toolbar) for quick access. It would be too laborious to put a long list of files in the mode tag, especially when it could easily change. (Thanks to Alan E. for this)

The macro (very simple, once you know the syntax):

buffer.setMode("nameofmymode");


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From: Dale Anson
Here is how the mode is selected by jEdit.

1) the filename is an exact match for the filename glob.
2) the filename matches the filename glob and the first line of the file matches the first line glob
3) the filename matches the filename glob
4) the first line of the file matches the first line glob

new edit mode line of code didn't show up in my initial post...

< MODE NAME="ToDo" FILE="ToDo.xml" FIRST_LINE_GLOB="*# ToDoFile*" / >