Having some experience photographing fireworks, I can tell you that shooting from your garage is feasible, but there are pitfalls.

How are you going to set up your exposure and your focus in advance? I have found that f2.8 @ 1/30 second works for me, with an ISO setting of 800, but YMMV.

The idea of time exposures is heading in the right direction, but I think you are underestimating the transience of fireworks explosions. You have about a 1/4 second window in which to catch the fireworks burst at or near optimum radiance. I found that I could not do this even when I was there operating the camera because between my reflex time and the shutter delay I was always too late. The chance of catching the proper moment with an unattended automaton taking the pictures is slim.

I finally (well, relatively quickly, actually) decided to give up on trying to "take pictures", and just zoomed out to a wide enough angle to catch the show, put the camera on continuous shooting (it ran at about one frame every second) and pointed it up into the sky, not even bothering to look through the viewfinder. This worked fairly well, out of 300+ exposures about 100 had something worth keeping.

However, if you're talking about eight hours of this, you better have a pretty big memory card because you will need about 28,000 exposures. That'll take about 120 GB at any decently high resolution. I guess if you can build in a timer to start everything up at the hour the show is scheduled to start...

tanstaafl.