All depends on the length of your video. If it's under 72 minutes or so, then you could use 8,000,000 CBR with 192kbps .AC3 audio. The DVD spec for maximum combined video and audio bitrate is right at 10Mbits, so 8.192Mbits is well under that and will look very good.
"...maintain the same level of quality but not skip or jump on playback?"
Are you having a problem with playback? If so, excessive bit rate can cause it but it's rare -- DVDA won't accept it [mpg2] without re-encoding if the rate is too high (off spec).
Just use the templates in Vegas, and be aware that quality will drop the lower the bit rate... gets pretty noticeable as you approach 2 hours on a single layer DVD.