Ok, I figured it out (see below, fellow newbies), but have a few more questions:
1) It looks like I've lost some information in the resultant 'mpg'. Is there any way to retain all or most of it?
2) Will my DVD player accept any other codecs other than mpeg1? For example, could I use DivX5 or something else (anything that could make higher quality video?)
mencoder -of mpeg -oac copy -ovc lavc -lavcopts vcodec=mpeg1video '/file/video.avi' -o output.mpg