There are a number of electric body shaver options now available, including the Norelco line of BodyGroom trimmers, made for a man's body. They're available worldwide, or directly by mail online. And there's always a simple razor, a disposable will do in the shower. I favor a women's razor, intended for the body, I think a little more gentle than a man's facial razor, especially around the tender bits.
If you have back hair you may need a shower partner to help you (always fun in itself, unless you're a contortionist). I've seen attachments for a razor online, sorta like the back scrubber idea, but you'll have to Google it.
Depilatories use harsh chemicals, I don't recommend them. And I'm not sure they really remove the root, rather partially dissolve the hair at the skin line, so it can be wiped away.