Yea,
Check the mileage fee on the truck that you will be renting.
Some of the small "In town" vans do not have the V10, but would have a 5.4L V8 making 300 HP in the pickups, less in the vans. Van front cube vans make less power than the pickups.
Are you thinking about renting a gas powered F-650 heavy duty truck? They typically will get lousy mileage, as they tend to have 5.12:1 rear ends, or lower ratio, to give it the ability to tow and carry many thousands of pounds, so 4 and 5 MPG is not unheard of.
You did mention 10 trips a year, about 200 Km each, or about 2000 Km a year. Figure out what that cost will be, and consider a 1995 - 2002 gas pickup with a V10 or the old V8 460" engine. You might even find a 8.1L V8 GMC for sale at a reasonable cost. Consider if you only pay about $5,000 - 8,000, the cost will not reduce to much after the next 4 years, if you are only adding 10,000 miles. By this time, most have already lost all their drive off value, what is left will pretty much stay there, and you should be able to resell for about the same amount.
Yet if you also consider the insurance, what U-haul sells is pretty expensive, but so is insurance on a vehicle you are not driving. With my motorhome, I can call my agent and tell him to leave it dormant while I am not driving it, so the most expensive liability is in-activated, while the fire, theft, and damage is still in effect.
Fred.