Creating Walking Directions (Best Method)

In the next few weeks, I’m planning to start a fairly large project (at least by my standards). The application will display an existing map of my campus, and it should allow users to select a source and destination from the list of 200 or so buildings on the map. Once the beginning and end points have been selected, the program will calculate the shortest possible route that connects these locations (staying on the roads and walking paths, of course…if only a straight line would suffice…meh). At first, I was planning to make 1 swf that does everything…it would have the coordinates of all buildings and intersections, and it would go through every possible combination in search of the shortest path. As I considered this more, though, I realized that Flash might not be able to handle all the recursion (at least, I think that’s what the technique is called), and if it could, it might be quite taxing on some people’s computers. So then, I began considering alternative possibilities. As I was thinking of the technique through which this task might be accomplished, a relational database kept coming to mind…I’m not sure what the standard is for this kind of thing, but for some reason, I’m thinking a db might be it. Either way, I’d like to avoid a database if at all possible. I’m most comfortable with Actionscript, I’m at an intermiediate level with C++ (though I don’t even know if this option would be possible), and I’ve used ASP and PHP before, but that use has been somewhat limited. If I could, I’d like to use a language that I already know, but I was wondering what would be best. I’m currently leaning toward ASP, but I really know next to nothing about the pros and cons of languages. Anyway, what should happen is the user selects (in Flash) the source and destination, Flash sends these values to (?), there, (?) matches Flash’s string values with coordinates, handles the calculations, returns the shortest route back to Flash, then Flash will scale the coordinates appropriately and draw the path on the map. And that should be it. I’ve never coded anything like this before, but I think I will be able to handle it over time. I’d appreciate any input as far as language choice goes, and really any other suggestions or words of advice. Thanks in advance.