I don't know what exactly your plan is, but if you actually want people to do real-time missions with theit ships you will horribly screw up MP-timescale when doing this. (as in: The one who encounters something will be significantly later at the destination than the one who doesn't just because of he timescaling. If you just want to simulate one go as a "testrun" without any competition or whatsoever, that system could work.
Nevertheless, you need some sort of warpfield/hyperspace/jumpgates to make interstellar travel possible in a human timescale. Or else you would need at least 4.5 years (!) to reach the nearest star, increasing fast to 10 years if you want more than a few solar systems. For a list of nearest stars and theit distance (conveniently in lightyears) see Wikipedia:
http://en.wikipedia.org/wiki/List_of_nearest_stars