See why asking this is worse than asking which color tractor is better?  Everyone has an opinion, but they can back it up with facts and experience.  Personally I have 2 old Chevy's and an old Ford.

We replaced a couple Chevy single axles this winter with a tandem Chevy and a twin screw Ford.  Both of them had been old propane trucks.  The 76 had been converted back to gasoline, the 95 was still on propane. The 76 will probably be parted out.  The 95 will be in Werhle's ad one of these days but they will probably take it off propane (a mistake but gasoline sells better that an LP fueled truck) and paint it.  Great truck, but a 14 ft bed just wasn't big enough for our operation.  By the time I modified it replacing it made more sense.

A mechanic friend warned me not to buy an old International.  (old = older than late 70"s )  He says there are some critical parts for older (especially pre 70's) Internationals that are just not available.  That however may become common. I have a 2001 Dodge Dakota that needed the ignition switch replaced.  Local CarQuest store found one on the shelf at a parts house in Michigan.  Dodge, NAPA, CarQuest, and O'Reilly's all said it was on national back order and not available.  With more and more auto parts suppliers shut down this may become an issue.  But I'm getting side tracked.

How much you want to invest, how far you need to haul, how much capacity, hauling just to the farm to to a processor, license (both the truck and the drivers), insurance, all these are head scratchers. Toss us a few more details and we'll try to confuse you further.