I apologize for it not being that simple...This is not just a matter of tags (attributes), which indeed will be of issue if BLM GTLF is the original source, as BLM has errors in route type designations (255 documented instances just in the Murphy subregion). But basically the map is missing many features approved in 2009 as public trails on BLM ground, just on review of the BLM's Murphy Travel Management area. 
Without some ability to merge datasets, consume data remotely like a REST service, I cannot begin to demonstrate the breadth of the issue, nor to begin a rational process and list the issues between the Trails presentation within OpenStreetMaps and reality.
What I know to be validated correct and representative of the authoritative map data --with corrections that BLM has been unable to implement in its own data, is the IDPR Idaho Trails geodata and map presentation linked in the original comment. Not sure where to go from here on such a high-altitude issue. I'll begin working with the Trails working group going forward, so hopefully there will be high-level approach to deal with the larger issue of accurate presentation of trails within OpenStreets' geodata..