I would recommend you pull all the tools and gears needed together first.  Then you can determine the size of the pack that would be needed.  Consider the number of day's you may be out and the hiking gear needed for that.   Once that is done, look for packs made from VERY durable materials that includes the storage the way you like it.  Alternatively, if your on a budget you could stop by a army surplus store and pick up something that will work.  We appreciate the trail maintainers!    

Superusers do not speak on behalf of REI and may have received
one or more gifts or other benefits from the co-op.