I never seen a map with uh.. so many routes. Layout looks interesting, I'd love to try out this map someday.
I like the colors too, except maybe red/blue part is a bit too saturated.
But yeah.. you went way overboard with polygons. You need to go over your map and optimize it - delete all unnecessary polygons. For example, outside of the map is made of 2 extra layers of polygons which increases polycount by about 500.
There's absolutely no reason to keep that 2nd layer. 1st layer is necessary for shading I suppose, but you can still reduce polycount there like I've shown on the picture.
See polygons1.jpg (at the bottom).
There's a lot of unnecessary polygons in the islands themselves - delete some polygons inside the islands and join vertices.
More importantly - delete some polygons on the outside of islands as they will cause a lot of polybugs. There are a lot of places where you have a straight surface split into several fragments.
See polygons2.jpg (at the bottom).
Other than polycount/polybug issues it seems decent, especially for the first map. But I'll save "good job" until you optimise it.
I suggest you look at one of my maps (in the sig) at how I do polybug fixing. Or someone else's maps. Either way it'd be a good experience for you if you look at how maps by other mappers are made.
Good luck