Hi, and welcome to the board. You've come to a good place full of great people.
For finding a diesel, as far as I know (not too far sometimes <img src="/forums/images/graemlins/smile.gif" alt="" />), diesels weren't as popular in the US as maybe they were in Canada, so finding a 20 year old truck may be more
difficult. I suggest you place ads in the local papers and Truck Trader type publications under the Want ads. Maybe something to the effect of ; "Wanted: Isuzu pick-up, any year, must be diesel and in running or repairable condition." The repairable condition may just mean that sometimes people can't get the ol' diesel to start and figure it's beyond help, when maybe all it needs are new glowplugs. Who knows.
Placing ads in malls and anywhere else free is an idea also.
Best of luck, I hope this helps. <img src="/forums/images/graemlins/kewl.gif" alt="" />