I fixed those two fields. I can't even find the light brown with furrows that I thought I used. Maybe I hallucinated them. ;-)

In fixing this, I noticed that the paved road on the left was accidentally on the ROADS sheet instead of the ROADS PAVED sheet. Fixed it after exporting this JPEG.

Here's a close-up of the fields. The two empty ones were furrowed brown fields. Not sure why those fills disappeared. (I just checked, and they now have a fill style of Hollow. Hmmm.)

Following my test runs with the village of Greenwood Falls (population 920) and Redway Hill Township (population ~3,500), here's my attempt at a major city: Wolfwell Falls (population ~55,000).

This is what Watabou gave me to work with:

And this is what I came up with:

Here's a close-up of the Castle District, which I figure is a bit more upscale.

(I kind of messed up the river there. I when I did the "Change like drawing tool" command, I accidentally wasn't on the River/Water sheet, and I think when I fixed it I messed up the top layer or something.)

The nicer neighborhoods have a lot more greenery. Most neighborhoods have more dirt than greenery, and the area by the docks is muddier.

As predicted in the Redway Hill Towship thread, the longest part was redrawing the secondary roads. According to the Info: Count tool, there are 59 paved roads and 948 unpaved roads! I hope I successfully converted and/or deleted-and-redrew all of the roads. I had to do all of that, and also create a handful of special buildings, before being able to convert everything left to be the regular buildings. If you see any really weird buildings, it might be something I didn't properly convert to whatever it was supposed to be before turning it into a building.

I should draw a lot more fields -- the ones on the north side of the city won't be enough to sustain a city of 55,000 people! (Also, I just noticed that I call it "Wolfwell Hall" on the map instead of Wolfwell Falls. Gotta fix that.)

Okay, here's a larger town. I kept getting interruptions, but I'd say it took me about two hours. This time I imported the trees, but I must have been doing something wrong when I changed like draw tool, because I was just getting the outlines. I ended up manually adding the trees using the draw tool.

With this map and my previous ones, I changed the buildings in small batches, by blocks or neighborhoods. I did that in part because I kept missing roads, and then adding them as I was going neighborhood by neighborhood. When I tackle a big city, I will try it where I do everything else first, eliminate extraneous non-building import lines, and then select everything left to convert into buildings.

This is what Watabou gave me:

And this is what I turned it into:

Yes, I did use the draw tools for the trees - worked great! For the river, I used "Change like draw tool" to change it to the 75-foot river. I also used the "Change like draw tool" for the sea (the straight closed polygon water tool), the three main roads, the round towers, the square gatehouse towers, the docks, the parks, and the buildings. I used the draw tools (but not the "Change like draw tools") for the city walls, the bridges, the trees, the darker grass beneath the trees directly to the south-east of the castle, the fields, the hedges, the dirt roads, the town square, and the forest on the north side of the map. For the heraldic symbol, I did as you advised, moving the components to the appropriate sheets and changing to a solid color. (Interestingly, the deer didn't fill in completely, just the outline.)

There were some minor issues that had to do with how Watabou exported the data. The river was in multiple sections, broken by the bridges, and the stretch between the final bridge and the sea wasn't there at all, so I did that part using the draw tools. The major road coming in from the west continued up the river a bit, so I had to trim off that part. Same with the road coming in from the south: it continued down the river from where I put the wooden bridge. So you just have to pay attention to what's being changed to make sure the right things are being changed properly, knowing that you might have to trim a bit here and there, or use the drawing tools to add a bit.

But overall, worked great! I am going to do a larger town now, and will time it to see how long it takes.