Happy Birthday, Toady.
I removed part of roads to change road graph into tree. It can be addition to existing implementation.
Why would you voluntarily create road trees and blind alleys? The very purpose of roads is that they enable people getting from somewhere to somewhere else - in case of the farms, the roads should offer a straight and simple connection to the town. Even Toady's original roads were too twisted and nonsensical, why would you complicate them even more?
To make Jiri's point a little more directly, the problem isn't just that there are too many roads, but that they're heading in the wrong directions.
There are two things those roads should be heading towards - either they head into the middle of town, and their markets, or they head into the nearest existing more major road, which takes them either to the middle of town, and its market, or out along a major trade road.
You need to start, once again, with the rivers and major roads and the major job-creating centers of towns (right now, the castle, although hopefully, at some point, the market will be the center of town, or A center of town), and then draw other supporting roads around them, as a way of getting to the major roads.
These roads should not look like a grid in any way. They should look like tributaries from a river - small streams joining up to make major rivers as all the traffic consolidates into a major flow.
I made the most important roads yellow, orange be an intermediate road that is only important in getting across the river, and the red roads be the "tributaries" that are minor roads that are still more important than the dark brown paths. I left the city roads alone.
I also highlighted in purple a completely pointless bridge crossing the river just to place one extra house on the riverbank.
All of these paths are just the quickest path for every house to reach the nearest minor tributary road.
These tributary roads I selected fairly arbitrarily, just to make them spaced apart a little, and reach out to a swath of farmland, and make the isolated houses have a little bit easier access to the tributary roads.
More organically, the tributary roads would come first, and the farms would be built to take advantage of the access to the closest road.
Still, this is leaving all the roads that were generated by the current code intact, but just "hiding" the useless ones. You can tell the sometimes bizarre angular bends in the roads probably shouldn't be there at a glance.