I have a Vegas 6d timeline with a bunch of markers on it.
Is there some easy way to export a simple text file listing the position of each marker, listing either timecode and/or absolute frame number?
Use the Edit Details (View Menu). Select Markers. Then click on the blank "button" at the intersection of the row and column headers. This will select everything. Press Ctrl-C to copy. Paste to your favorite spreadsheet and you can take if from there.
You can also use that view to rename and delete markers (by selecting the entire row and then pressing the delete key). Very handy for making large-scale changes. You can also import the marker labels into a WP for spell checking, something useful if you are using the markers as input to DVDA chapter markers.