I only looked at one screenshot which was the first one and I found a lot of problems. For one, you used the wrong high mountain tiles. They are ick, what you do is press 'W' in the predefined objects for Standard, and there will be all kinds of water mountain tiles. Copy and paste
parts of them onto your mountain to make it look normal. Also, the levels are not very detailed.. When I have open patches oh grass, I fill them with puffy grass, flowers, swamp, or whatever else I can use to fill them that fits the current area. Cut down bushes too, the little peg things.
I hope this helps you out a bit.