Thanks for all the advice everyone, much appreciated.
Finished the strip down over the weekend and have the cab ready to be sand blasted and repaired. Once I get the cab away I will take the rolling chassis to a steam cleaner for a wash down. Depending how it comes up will determine what I do with it next, don't really want to strip it down any more but I do want to give the chassis a coating of something to freshen it up. What do people recommend?