Star trail shots are addictive. I always make time to take them when opportunity arises.
For me, just a photo of star trails without landscape or any other subject in the photo is boring, so I always make an effort to capture the landscape as well. That said, things get complicated really quickly. First of all, what time of the night and which direction you are shooting matters. I've shot a photo on at 6000ft in the mountain top, 2 hours after the sun set at west, exposing for 30min. The result is a sunset looking horizon with star trails in the sky closer to me. It's totally unexpected, but really fun. Plus, I shoot 35mm, so there's no way to find out until I get my negatives back and run them through the scanner.
You may also want to think about how to light the subjects in the photo. I've used the tail lamp of a car to light up a tree while letting the stars spin in the background. I've also happened to be on the other side of the full moon which lit the light house tower for me with stars in the background. You can either plan for it, or you can just do it and see what happens.
Using film on long exposure may not have overheating sensor problem of DSLRs, but film also becomes grainy after some time. I don't really know how it works yet. Stacking won't work very well for me. There are too many variables for me. First, alignment of the negative between frames may not be precised. Secondly, alignment of negatives on the scanner has pretty bad tolerances. Plus, I just like to see what light accumulates in the sky beyond just the stars, so I'd rather do it all on one frame.
Oh, I read that the different color of the stars indicate different temperature at which they are burning.