+1 to the above advice, with an addition that I do, which is that I keep all of the sample libraries and such also on my data drive, and not on the OS drive.
That's a good use of that configuration, and should work well. It's how I have my desktop set up, as well, and I never have any performance issues, even with the samples streaming from the same drive as where the projects and their audio go.
And yes, backing up to the external drive is an essential thing to do, unless you like rebuilding things from scratch.
Bob Bone