I don't know about installing elsewhere, but if your machine dies, you just reinstall. TG is relatively small. The files you gather using TG are best be kept elsewhere indeed, but you can choose where. I have a special folder on partition E, which I empty now and again.
Before you start working with TG, remember to keep your assets in an easy place with a clear structure that doesn't change, like a library. If you change naming, or place of that library (where trees and such are called from), opening older files may get you warnings that assets can't be found because you moved them.
Have fun with TG and welcome, btw.