I use an apron (+1)and rely upon it for rigidity, but it isn't attached to the legs at all....
This is my design of a portable workbench, which packs down to 6' x 1' x 1' roughly and can go in a car.
I think you should take a look at the rip fence. It may not be prefectly parrallel to the blade, or is it from using the saw blade on one side when skimming stock down to size?
