Alan_D: I wouldn't like to try to use it for any form of navigation
Why buy a GPS if you're not going to use it for *any* form of navigation?
If the OP is prepared to learn how to use their new GPS properly, then they will be able to navigate safely with it accompanied by a chart with lines drawn on it.
A moving map obviously gives much better situational awareness and would probably have been a better investment, but for following a line on a chart - just about any GPS will do that.