The autogen is based on X-Plane autogen. Unfortunately, the tools to make these kinds of adjustments (with the exception of roads) do not exist for X-Plane in an efficient manner. Andras has published great packages for tree data, and there are also great OSM download locations here for roads and objects: http://scenery.osm2xp.com/north%20america/us/ The above can be overlaid on the Oregon scenery and will replace the autogen as you currently see it. Please keep in mind that Oregon is a legacy scenery product. The "enhanced" line of products contain the latest and greatest, but at this time is limited to Oahu, Reno, and the soon to be released NORCAL package.