seems like a pretty small unit to road?
Not at all.
Here in Europe, the ancestors own multiple small pieces of lands spread all over small villages. Over time, their children and grand children inherit those pieces of land. So this is one of the biggest reasons we tend to road our tractors so much on this side of the pond. Distance varies a lot accordingly to various factors but usually no more than 4 or 5 miles.
Over here, any road legal trailer above 1650 lbs gross weight has to have brakes. In the case of agricultural trailers, they often have hydraulic brakes and the tractor is fitted with a brake valve tied to the brake pedal or they just use a single remote from the tractor to engage the brakes.
These little tractors like the Agria often get a 6600 lbs braked tow rating or 1650 lbs non braked.
When it's grape harvest time, you should see all the little tractors on the road pulling trailers full of grapes so they can go unload on the wineries. They make this huge lines on the roads near the wineries as they wait to unload.
On winter time, you would see trailers full of logs that people take home to cut, split and burn for firewood. Or even loaded with pine needles so they can use it as bedding material for the cattle.
As luck would have it, I was looking for some pictures during grape harvest to show you as an example and ended up finding one with a little Agria just like mine. A bit hard to see, but you can see the trailer in the back with the containers filled with grapes.