APrague: What to do to be proactive about pickpockets in Prague?
It is a problem in the crowded areas such as the view of Prague from the Castle (Na Opyši), the Charles bridge or the spot in front of the Astronomical clock in Prague. So hold on to your purse and watch around a bit.
ABudapest: Best places in Central Europe?
Olomouc is definitely a good choice, Brno would be another one. You can also think about exploring Slovakia.
AIsrael: What are the best ways to go from Tel Aviv to Jerusalém?
Definitely bus, but if you want to see the countryside, take the train to Bet Shemesh St and then another one to Jerusalem. Beautiful views as you near the holy city.