You could re-render at a lower bitrate. What is the total running time of all the video in the project? If under an hour and twenty minutes (or thereabouts) you can fit it all on a single layer DVD without much loss of quality.
The more correct way would be to use DL blanks, reduce the size of your project, or turn it into 2 projects that would be split across 2 SL DVDs. There are threads on the 1st two in this forum, as well as a olot of info at videohelp.com & doom9.org.
There are also ripping-oriented programs that are intended to split the average retail DL DVD across 2 single layer blanks. I've never used one so I can't comment on their accuracy in preserving menus. You can find trial & free software through the above 2 sites including different versions of DVDFab.
Thanks for all the good ideas. I really just put to much (3 + hrs) in a single project.
I went back into vegas split the original into three segments and rendered again. Thanks for taking the time to answer.