Downloadable tour planner map

We're now the proud owners of a little Rapido pop-top from 2000: only three days of ownership and still to go anywhere together, so we're planning a Scottish expedition for Spring. At present we're in the early stages of assembling lists of possible sites, variants on the route, etc. I keep thinking we need a large map to stick pins in, linked to information about possible sites.
But then I wonder if there's a computer version of the same idea, to save vast WWII style map boards with bits of ribbon all over the place, or writing so much on a paper map that it needs replacing every time we have a new idea.

I haven't found one in initial looking, but then I'm not enough of a geek to be quite sure what to search for.

Oh, and it'll have to work on Linux Ubuntu, as well, since we abandoned Windows a few years ago. (Infinitely cheaper, plus much happier users here!)

Thanks for any suggestions, especially if they're easy to use!

Richard