I think your way is the fastest since the TC burn-in is a realtime effect.
But if that's not an option, I've always exported a Quicktime Reference (which comes with a render time wait) and use Adobe Media Encoder to compress the MPEG DVD files, and DVDSP to burn the disk. I've found Media Encoder faster than Compressor and Sorenson. Since that's not an option, though, I'd go with Compressor. The presets are guaranteed to work with DVDSP, so no re-encoding will be going on there. If DVDSP doesn't like the Sorenson output it will reprocess everything, and the last time I used Sorenson it was buggy and not that fast. I don't even install it anymore.
I would export a self contained quicktime from Avid, using Avid's timecode burn. Then compress to MPEG 2 in compressor, then create a DVD in DVD Studio Pro. You can compress using the "Fastest Encode" template in Compressor to speed it up a bit.
While you can use compressor to add the timecode burn, I never do because you can't add a window or a drop shadow to the TC burn, so sometimes if your footage gets very white around the edges, the burn can be hard to read.
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"We are the facilitators of our own creative evolution." - Bill Hicks
When trying to create BITC I've found that Compressor dislikes the DNxHD codec when sourcing the timecode within an Avid exported QT. First frame looks fine, then the BG image fades to almost black and doesn't move. I've had this happen with Same as Source and Ref exports.
If they're on a Mac, I'd export as Prores and then create the mpeg file though Compressor. Not as fast as a ref QT, but pretty quick. If they've captured as ProRes then a ref QT should also work fine.
The idea of rendering the TC burn window in the Avid just doesn't appeal to me.
Alternatively if you know the start TC of your Ref export, you could try some other encoder that lets you add a custom TC value if they cannot read the embedded TC.