Do we need to illustrate all of the locations of existing interpretive panels on the route map even if the panels do not relate to the byway?
No. You want to provide reviewers with enough information to determine whether or not your byway is ready for visitors, and where possible, provide them with a sense of the visitor experience. For example, these panels might be thematic (e.g., historic, with a focus on battlefield sites). In such instances, you may want to create an icon for historic markers/panels for your Route Map and provide additional detail on specific markers/panels in section 5 of the application (Visitor Experience) under the Evidence of Intrinsic Quality(s) section to support the Intrinsic Quality(s) for which you are nominating the road.