I have a cheap prepaid LG dumbphone for similar reasons; it's nice to be not email accessible for at least part of the day.

I also have an iPod Touch, which would solve your instapaper problem.

The only problem I can't solve is maps... obviously you can get maps on the iPod, but only when you have wifi, and if you have wifi you're probably not lost. There's always the separate GPS unit solution; you wouldn't want to carry it around all the time though.