jajef, how many possible origin and destination points are you talking about? For a huge number, it's called Google Maps or a portable GPS :-). If it's a really small list, I could imagine an HTML imagemap, where clicking on a region or point kicks you to a second-level page whose start-point is highlighted, and the other points now link to yet a third level of images, each of which shows an A to B route. Do you need this done for you, or (preferable) do you want to know how you might do it yourself? What drawing or mapping tools and skills do you have? Do you know anything at all about web page coding? What I describe is clunky but straightforward, if that combination of adjectives makes sense.

I'm describing a series of distinct maps, but since they would be all matched to one another, changing maps would make a route or endpoint "appear". If you want more action, the route maps could be animated gifs, which progressively show part, then more, then all of that path, winding up and staying at the "all" variation.