I have lots of single file DJ mixes in Roon. I don’t necessary want to add cuesheets, but I would like to add the rough tracklists as data to these files so I can reference the tracklists with ease. What’s the generally accepted best way to do so?
I don’t think you can..
In fact you can’t even do it with .cue sheets even if you wanted to 
The best you can do is generate and add a .pdf file containing the tracklist into the same folder as your mix, but that only really works if you have one mix per folder.
There’s an almost 10 year old request 
for a notes feature or a clickable url field you might want to add your vote to that request for all the good that may or may not do.
Not really a solution, but if your tracklist is available externally at say mixesdb.com you code add the URL as the catalogue ID or product ID field in Roon which will show up under credits although it’s not clickable and you can only apply it at the ‘album’ level. You could take a similar approach with the CATALOGNUMBER or UPC fields in the file metadata itself which I think applies at the track level. But again not really a proper solution.
You could hijack a lesser used Roon field and add the whole tracklist as a big blog of text, someone in this thread suggests using the location field. But again no linking, either in Roon itself or externally.
Like you I’d love to see a nice solution to this. I have a huge number of mixes and old radio shows, it would be great to be able to properly catalog them in Roon and be able to link out to my wider Roon library from individual tracks or a track-listing. But even just having the ability to add notes in markdown format or other standardised format that then rendered nicely in Roon would be a huge step forward to what the have now.
That would also open the doors for an external script to pull across matching playlists from mixesdb.com or even generate them automatically using an acoustic ID library and then populate the required fields in Roon via file tags or an API call.
Anyone else got any good ideas? How do other Roon users handle this?