K.C.
Although I haven't done bus trips with small children, I DID do the two hour bus trip from Philadelphia to NYC. It cost under $20 round-trip (which is cheap). HOWEVER, to be totally honest, they pack you in like sardines, chances of getting a decent seat are pretty bad, it's dark and cramped and generally uncomfortable. It was actually pretty awful and the thought of doing SIX hours of that with a 3 and 5yr old...well, quite frankly, I'm shuddering at the thought (and I've done many, many 14 hour plane rides with 3 children, so I'm somewhat experienced in the whole travel-with-kids scenario). I guess, what I'm saying, is that unless it's your ONLY option, I would sincerely re-think the bus thing. Of course, $15 is hard to beat...