You can tweak the Grass color either by using the TC client mod and set it on the BiomeConfig. Or use “ReplaceToBiomename” to replace it to a Biome that has the color you like. This would be Savanna I think.
As for te actual Terrain, it looks very much HandMade. (Note the Hard border to the right).
For the Road, there are some Approaches, but I dont think roads come out very good on Terrain Generation.
You could use River biomes, which would prevent you from using Rivers. Or you could have two different Biomes with the same Settings and a Border Biome between them.
You can Calm down the Terrain if you use a very low Volatility. If you mess with the Volatility1 and 2 values. you should be able to add these hills.
For the second screen:
Looks also handmade. If you want mountains like this, you will have to use mutliple biomes nested inside each other. Maybe with some fancy Border Settings.
Your friend here is the Smooth Radis. Aswell as MaxAverageHeight.
Also, use low volatility values, as you want a calm mountain.
Otherwise, you could add Custom Structure Mountains. They “could” look awesome. But would take quite the amount of work.
As for MobSpawning:
Without additonal Plugins (Like Denizen) this is not Possible.