I thought you already used the tilemap, that should probably help too
I am kinda scrappy for this kind of things (or how I like to call it: "creative").
The way I did it was using plain-colored square and triangle sprites for ground collisions and then creating a tiled sprite with the dimensions of each square to give it texture, then the grass and borders are made with the "beveled edges" visual effect applied to a whole layer (this is also true for the mud/dirt) which is probably HIGHLY inefficient, but I felt proud of coming up with that whole shabang.