I think that Steve: overlooked one, small thing. The use of plain water won't soften the glue, unless it's a mix of the 'old fashioned stuff' of water and flour. If the wallpaper glue/adhesive is 'modern', you'll need something to soften it up.
I would like to spare myself a 'duplication of effort' in giving you my advice, and instead, refer you to a past Follow-up I did on the same subject. See Popular Question.