It needs a slight bump texture to keep it from looking like plastic. You can also use rocks and plants and bushes to hide where it meets the grass to make it look more natural. I sometimes touch up such spots by hand in photoshop but if you do it right it's unnessesary. Also don't forget about mixing materials. You can do a lot with environment blending. You also might want to try to make a road less traveled with something simple and small that you can place lots of to make a good looking path. I like it. Don't give up yet.