My TTL-232R-3V3-AJ USB cables arrived last week (I ordered a spare), a quick test after installing the OS X driver indicated that I was indeed seeing a new serial port after plugging the cable in, so it was now time to replace my hacked Keyspan interface with a clean looking 3.5mm stereo audio jack on my WRT. Having it in the back with the other ports would have been ideal, but there was just no real estate left. I opted for the top case opposite the antenna jack.
I wish now that I'd had some heat shrink tubing on hand for the jack, but I'm not planning to go back to fix that unless I have to. A quick desoldering of my old cable from the underside of the board and soldering the new cable to the top of the board and I was in business.