Wow... Ok, yes - these trucks will run fine on VO with no 'conversion', right up until they don't run 'fine' anymore - and then its too late. MANY people have figured this out the hard way after touting that a conversion wasn't necessary - but in the years I've been doing this, they almost never come back and say they were wrong. I am generally skeptical of those who claim they have had long-term success, but think certain environments and the way the truck is used can lend itself to longer 'success' than others.
Anyway, to answer your questions - yes, there is a proven method for being able to run your truck on WVO for 100's of 1000's of miles without problems. I have 170,000 miles on VO in my dually and 100k on my Excursion and have yet to have the first VO-related issue.
In a nutshell, you need to be able to remove all of the VO from the engine before ya shut it down. To do this, ya need a 2nd fuel system that mimics the stock system and you need to keep 100% of the VO out of the diesel tank. You'll 'purge' the VO from the injectors and heads before shutdown. Additionally, the VO will need to be heated so it atomizes properly thru the injectors. Anything less has a long track record of failure.
As far as dewatering, the easiest/cheapest method is simple Heat & Settle. The water is heavier than the oil, so left alone it will eventually separate. We expedite this process by warming the oil up (110-120* is plenty) to reduce the viscosity so the water can 'fall out' easier. Then, with the heat off, let it settle for 48 hrs or longer and drain the water off the bottom. At this point, you can test the oil for water and if its 'dry' at the bottom - the rest will be dry too.
I strain the chunks and large spices etc out using nylon paint strainer bags (~200mic - not much more than window screen) before dewatering. Then, I used blue jean legs sewn into 'bag filters' as my initial filter for a loooong time. These are CHEAP/free and can be very effective at making your 'real' filters last longer. Although effective, the oil needs to be warm and they are still SLOW... By real filters, I mean absolute-rated FUEL filters. I suggest using a 10mic goldenrod transfer tank-type filter as a minimum and recommend using a 2mic spin-on fuel filter as a final filter. This combo of H&S and filters provides me with 15-20k miles on the on-truck fuel filters.
Water filters and other compromised solutions don't work as well and are ultimately less cost effective anyway. Water-Block filters cannot/will not/do not 'remove' water from WVO - but they do cost more. Don't waste your $$$.
I'd be happy to be more specific about the conversion and share part#'s, sources, etc for the filtering stuff.
CC flatbed - headstuds, AC codes, T4/S366, custom leather interior, '07 facelift, big honkin bumper, 180k miles on DIY veggie conversion and a few other things...
, Limited, 4x4, BTS trans, 120k on veggie! - wrecked spring 2013 - RIP