Once this mission becomes available, return to your safehouse and get some rest. This will be followed by a cutscene. After the scene, walk with Boozer down to your Bike. Once you’re near your bike, ride it so Boozer can hop on.
From hereon, you’ll be travelling to a new region down south, to a Camp called Lost Lake. Just follow the GPS Markers until you reach the mission marker. From there, another cutscene will play and this mission will be complete.