You ask for skinmesh import then say all you need is a script

As far as easy goes, Google Sketchup is as easy as you can get. And I agree with everyone else, that Sketchup is very limited. But it has the best plugin right in the program. Though if you have a modeling program that exports to .x, then the importer works like magic
As far as scripting goes, you will have to get a basic understanding of scripting and what each thing does. You will not get too far with out a basic understanding.
If you want to make a game, you will need to do that. Asking some one else to do the whole scripting for you then its not your game anymore
Another thing is also, where is your spacecraft? is it on the ground, is it hovering, is it in space? Look at Shadmars wipeout demo
http://www.3drad.com/forum/index.php?topic=2968.0That one can easily be converted to a space flying demo. changing the water level can be like changing the levetation height, speed and other things can follow. Not sure but maybe it can give you a start
