kobe.pole on 09 Nov, 2018 05:43 PM
There is no specific way to do this on CalTopo, as we do not create the maps, we import the data from various sources. Your best bet would be to go to Open Street maps, and make your changes there. We pull updates from there every few months.
As an OSM cartographer I'll say this: A trail is a trail is a trail. It may be a private trail but it wouldn't be incorrect for it to be mapped. There are access tags that do get rendered on the map to show that a particular trail (or road) is private access but in certain situations it's good to know that a trail exists in spite of any access restrictions.