Have used it as a registered user and it is a very useful tool, tried it tonight without logging in and the google maps interface seems to be on a go slow
From the FAQ's
"TrailWise provides an interface to Google Maps, which is a great way to see all the tracks in an area.
Unregistered users can use this facility, but only a limited part of the data will be displayed, just the basic geography & TRO info really.
Logged in users get to see more features. You can get to the facilty by clicking a hotlink in a selected tracks detail pages, or by using the 'Search' features to look around a given grid point."