If you are concerned about maximum power saving, then leaving the GPS and the cell radio active will be the biggest draw. There is nothing you can do about that really, unless you want to setup some kind of periodic wakeup/burst/disconnect kind of “idle” pattern to only enable things when in use. I’m not entirely sure doing that would give you much overall consumption saving unless your intervals were quite large, and if you’re talking about tracking/management/etc that might not make sense.
I think at this stage of the game you have things about as power-oriented as you can get. There are definitely more options for chopping down consumption, but then you’re also cutting out features that you want to use. So it’s a question from your side of choosing priorities.