To reset the trip odometer, go to the odometer page and press "menu". Then highlight reset and press "enter". Now you can select or deselect what you want or don't want to have reset.
To clear tracks, select "Tracks" from the main menu page. Then highlight "clear" and press enter. It takes a few seconds to clear.
Ensure that the prompt is turned on by going to the main menu. Highlight "set-up" and press "enter". Highlight "Routing" and press enter. Highlight "Guidance Method" and ensure "prompted" is selected. Now each time you hit go to a waypoint or geocache, you will be prompted for off road or follow road. If you select follow road and then want to switck to off road you have to go back and enter on go to again for that item so that you'll be prompted again.
Hope this helps.