Hi and welcome to TPunk!
In my opinion looks very rushed, I'd recommend dropping a couple of cities to focus on others more.
You also have to consider travelling time into your itinerary as it will often burn through entire days.
As for staying somewhere between Prague and Krakow I'd reccomend just adding another night to Krakow as it is a great city.
When I was overseas I used a Czech bus company called Student Agency. It was fantastic and very cheap and from the looks of it has expanded it's service a lot since then. check it out at , STUDENT AGENCY BUS, STUDENT AGENCY, STUDENT AGENCY ONLINE, BOOKING, PRAGUE