I won't comment on track/ballast textures as generally I dont use any. The paint tool simply is too big to to be splashing ballast about the countryside. I prefer my roadbed simple.
Now, getting into ground textures is a whole 'nuther bucket of worms......
I prefer my ground textures to be subtle toned down and color matched as close as possible. It's a workout going through the texture samples, trying out what works and what don't, but worth the effort. I have found four textures that I pretty much use as a ground cover base. They are:
KUID 328583:16036; JVC-(tx1); grass dirt......this is a dirt texture fine for track roadbed and along the sides of roads.
KUID:428217:558; d texture4...........a basic dirt texture mixed with the above texture for similar uses.
KUID:1987:9; A9;............Clumpy grass and dirt used at the edges of feilds, roads, etc.
KUID:2:53424:90001:1; Track Grass;............A basic grass texture best used mixed with other grass/dirt textures.
Highlighting the basic grass texture is, for me, a work in progress. However this flowered grass seems to work......KUID:328583:16038; JVC-(tx-1) Green Grass w/flowers.
As I mentioned above, it's a trail and error affair and very much subject to one's own view of the countryside.
For pix of how these textures appear in TS12, you can refer to my blog posts referenced below.
Good luck and keep on Trainzin'