yeah, put down blankets otherwise you'll scratch up the plastics, and maybe even the rear bumper.
Well, you don't have to secure it, and it won't move much unless you end up having to brake fast, or you take corners too fast, or hit a speed bump too fast... You know, drive sensibly and it shouldn't move much.
When you get home, the first thing you do before ever plugging it in is inspect the contents for anything that may have shifted. Make sure nothing fell out/off, or got disconnected. Look for bolts, quarters, stuff like that that may have bounced into exposed electronics.