Most supermods add a shipping map by dragging your radio out, as it's attached to it. However, that is a common shipping lane map. Someone actually made some maps for RSRD traffic based on the year recently, but I can't find it, but will look some more.
More helpful tools for RSRD is to know historical traffic, routes, ect. This is a great link. Study the dates, routes, ect and you can't miss. Sometimes it's better to pick a ambush point, rather than go looking where the actual battle took place.
http://www.historyanimated.com/pacificwaranimated/
Pay attention to the invasion campaigns as they're well scripted, such as Java, the largest of the game found off Java late Feb to early March.
The Solomons campaign is perfectly scripted by RSRD, you can easily do the battle of Coral Sea, battle of Saco, Battle of Santa Cruz, ect...You'll get flash messages for Santa Cruz in the game, but have to find the others.