There are a lot of great attorneys in Williamsport. You are right that in a lot of attorney's in smaller towns do handle more than one type of matter or as you put it jack of all trades. That does not mean that they don't know what they are doing in the criminal courts. I have worked as co counsel with some very good firms in Williamsport so I know that there are good attorneys in Central PA.
The best way to pick your attorney is to ask questions? What kind of Criminal Cases have they handled? How many have they handled? What percentage of their practice is criminal law? Best of Luck