Just as a FYI - Base Lake is a small lake in the South East corner of the map. The lake isn't shown on this map but is just North of the lake in the map above. It sits directly east of Offut AFB in the pink area (East of the RR Tracks).
From Old Town Bellevue (Mission Ave) take Hancock street South. Eventually Hancock turns into Harlan Lewis Road which will take you to Base Lake.