I added up all of my VHS video durations and it is about 280 mins. Can I fit all of this video onto one DVD and at what bitrate?

Divide the number of usable megabits in the DVD by the number of seconds of video you have. This will give you an estimate of the average bitrate you'll be forced to use. Of course, menus, data format, extra audio tracks, subs, etc., will also take up space, so that's a very optimistic average bitrate estimate. I wouldn't even try anything smaller than a DVD-9 for your purposes, even if you're talking about video animation. "If it ain't broke, upgrade anyway."

You can adjust the bit rate so that you can fit a fair bit on a DVD 4000kb/s is about 2.25 hrs. and 5000 kb/s is about 1.7 hrs. and so on. The trade off is that the lower the bit rate the lower the quality. The big problem you have is that VHS is not very good quality to start with (compared to DVD. It's a lot like connecting your computer to your TV... no matter what you do the picture sucks. So you can't cut quality too much more and still come away with a watchable DVD. With even a high quality VHS I would notgo lower than 5000kb/s Run your audio at about 224 khz... it will help to muffle someof the hiss found on any VHS tape.