Even my moderately light polluted urban house is a reasonable test location to approximate star photography exposures. I have used my trashbin-on-wheels to stand in for rock-like shapes.
As already said, 40 stacked exposures will forgive a LOT of noise! But those wide angle lenses have gobs of chromatic aberration, I think that would be the main thing to test for. Nothing shows up optical aberrations of any kind more than point light sources. You might be better off with something more like f8, and testing several focal lengths on the lens to find the optically best one.
I'm sure you're aware that the Milky Way can become a major player in astro landscapes. While star trails are pretty cool, the first thing that jumped into my head is a shot of a statue with a huge, sharp Milky Way in the background as a kind of counter monolith.
Anyway, I'm envious! Be sure to post some pictures.