I had the same problem this past winter with a Gillig that had sat for 15 years.
Look up toilet paper fuel filter on the web.
Make one or buy one.
Plumb it in before your regular fuel filters.
Change your fuel filters. Get two extra sets.
Put enough fuel in your tank to get where you want to be.
You may have to change the tp element on your way home, have some extra fuel in a jug along.
The tp filter should keep the crud out of your expensive filters.
Worked for me.
Let us know how it works out.
You can do it. For cheap!