WABDR Part 1: Bridge of the Gods to Packwood 

We completed part one of the WABDR that goes from the bottom border to top border of WA state.
The most helpful and useful off-roading map we have used and continue to use is GAIA. It is free to use (granted you can pay for content with a subscription but we use the free version) and is compatible with GPX files. It does not provide directions but is a GPS track so it will follow you as long as there is GPS signal. Most websites or a general google search can yield GPX files so this is an ideal app to use without spending additional money.
Another alternative to this is to use offline maps with Google Maps but this is limited to point to point travel when offline and can be difficult to use.