If you render a one hour fifty minute video, and don't have anything too fancy for menus, then when you do your render in Vegas to MPEG2, you need to use the NTSC DVD Architect template, NOT the NTSC template, and you need to click on the Custom button and change the bitrate from the default (which is 6,000,000) to 5,300,000. When this render is finished, you need to render the audio separately to an AC3 file using the AC3 stereo template.

To figure out the bitrate needed to exactly fit one DVD, use this bitrate calculator:

Bitrate Calculator

This calculator tells you what bitrate to use for a given length project. You want to use the highest bitrate possible (up to 8,000,000 bps) to get the best quality. However, if you want to fit more than one hour onto a single DVD, you must reduce the bitrate. I personally do not recommend going below 5,000,000 for any DVD created from high-quality DV video. Others disagree, but I think the video quality degradation gets to be pretty significant below this point, and is already starting to show when you get below 6,000,000. If you have Vegas 5.0, you might recover a little quality if you check the "2-pass" encoding checkox.

If you don't want to use the bitrate calculator, there is also a simple formula for calculating bitrate that can get you close:

B=600/T

B: total bitrate
T: total project time, in minutes

For your project (110 minutes), this gives 600/110 = 5.45 mbs. Thus, you would enter 5,450,000 into Vegas. I personally prefer the calculator, which in this case recommends a slightly lower rate of 5.315 (5,315,000) which I then rounded down in my recommendation above.