Don't have any expired charts for those areas.
But new ones are only $7.75 at MyPilotStore...with free shipping. Not too bad if you really want to keep sectionals.
I'd have to agree with others for the most part though.
Redundant devices and redundant power supply(s) are likely the best way to go.
I use both my cell phone and a cheap android tablet. Several of the cheaper android tablets have built in GPS.
Have Avare and FltPlanGo on my android devices for backup. Works a treat. And I have had to use it when the iPad wouldn't connect to GPS. (during a mock checkride)
As a suggestion, maybe see about borrowing one for the xcountry?
Whatever you decide, be safe, good luck, and enjoy the trip!