Working on my first adventure...

So I've decided to put together an adventure module for X-plorers. I have a kernel of a "cool idea" but it's turning out to be tougher than I imagined. Here's a quick, high-level glance at what I've got so far:

• New alien species? yes
• Weird technology?  yup
• Strange alien environment? affirmative
• Initial hook? yessiree
• Chapter hooks? Possibly...
• Artwork? Not yet (though I've been working off some inspiring pieces but I'll need some created at some point)

It's the melding of all these elements together that's kind of bogging me down a the moment. Frankly, part of this is that I'm stuck, spinning my wheels at the moment. So some sage advice (even if I've heard/read it before) would be motivating right about now.

With a dungeon enviroment, it would be simpler--just cordon off areas and drop in the baddies. But sci-fi kinda needs a bit more of a push. So does anyone have a favorite sandbox module or adventure resource that they like as far as structure goes? Layout suggestions would be a bit premature at this point.

Right now I'm looking for a good solid format for the info itself (organizing descriptions, stats, etc.).

Thoughts?