You can go straight from your camera or deck to vhs, most cams have a timecode display option,just set it to output.
Or, drop on the vegas timeline and add the timecode fx,course you then have to render. Hope this helps.
I do this exact same thing for my clients. Luckily it is easy to do.
There is a video "FX" tool to do this. Usually I set this on the main video track (rather than on particular events which you could also do). Look for the FX called Sonic Foundry Timecode.