Micheal,
The trouble is that there are multiple things that I want to stretch (extrude) at the same time, so there are multiple surfaces that need to be selected at once. In the jpg that I've included I've tried to circle all of the surfaces to illustrate. I've never been able to get them all selected at once so I could extend that whole thing. See if you can tell me how to extend that table base with the supporting 2x4's underneath and make them all longer.

Thanks,
Mark