40K: strategies to help my Ork Trukks/Battlewagons survive long enough to deliver their passengers into assault range?
The best way to get Battlewagons across the board, that I've see used, is to attach a Big Mek with a Kustom Force Field to the squad inside.  

This will make the Battlewagon(and I think every other vehicle within 6 inches of the Battlewagon) obscured.  A 4+ cover save should help you get across the board a little more consistently.