I have several shots captured from an old VHS tape that I'm trying to use in a PIP. I need to trim the lower 8 or so pixels & then resize the shot so that it fits into a 1/4 of the screen. Sure enough, the garbage bottom lines become visible as soon as I do the resize. The only way I've found so far is to crop, render to a new AVI, and then resize it. Is there a faster way to accomplish this? I'm using Vegas 6. TIA.

Put preview window in Best/Full. You should be able to see inverted fields.
Bump your pan/crop target downwards or upwards to find where the fields are inverting. You should be able to see that as well.
Force Resample may also help; prerender a short segment (Shift + B) to see what's going on.