For example, choose a color to indicate inaccessibility. Not for anybody, but for you. Color the map based on whether you can go there. Black could mean impossible, red with difficulty,
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Wallace River (Wikipedia)The Wallace River is a medium-sized river in Washington, United States. It is a tributary of the Skykomish River and joins near Sultan, just upstream from the mouth of the Sultan River. The Wallace River is 15 miles (24 km) long. Its drainage basin is 30 square miles (78 km2) in area.