I'm getting into Tirana around 8:30 in the morning(end of April). I'd like to get to Dubrovnik by the end of the day. How difficult is this trip by bus? Is the bus station close to the airport in Tirana? How long will the trip take? How much will it cost? Is it tough to find english speakers in Tirana? Any input is greatly appreciated.
I'm afraid you are looking for the holy grail in Balkan travels. As far as I know, no such transportation link exists. I would hazard a guess that you have set yourself an impossible task unless you find a flight connecting somewhere that will put you into DBV by nightfall (assume this will not be cheap).
About 3 years ago we did this but in the reverse direction.
Dubrovnik - Kotor 3-4 hours on a bus
Kotor-Ulcinj about 2 hrs - bus(my memory is sketchy on the duration)
Ulcinj - Skodhra 2 hrs (small bus only at 6 am)
Skodhra - Tirana 1.5 hrs
Note that we were in no hurry and so spent 2 nights in Kotor and another in Ulcinj.
English speakers are hard to come by in Tirana. Also, finding detail transport info is very difficult. I strongly suggest that if you are locked into this, do your research on the thorn tree forum (LP) to figure out how to get to DBV.
I talked to my brother who lives in Tirana. He thought that you may have a better chance to connect in Montenegro to Dubrovnik, but wasn't sure. Best case scenario, any type of bus trip would be at a minimum 12-14 hrs. He said maybe 20% Albanians may know some English, but even then, it's likely to be very broken. The bus connections are spotty at best. No idea of cost. Sorry, not much help.