Feb 13, 2016 - 9:37 AM
Hi arturo61, welcome to MySwissAlps!
The only way to tell for sure which rail pass works out best, is to make a detailed list of plans and then start calculating as explained here. Here are some further thoughts to consider: the Swiss Half Fare Card has one big advantage here, and that is that it's valid for all your trips. This includes Zurich Airport-Lucerne, trips made in and from Lucerne, trips in the Bernese Oberland and the Swiss leg of your outbound journey to Salzburg. The disadvantage is that it requires you to buy (discounted) tickets for each and every trip, which isn't very convenient.
If you'd like to have the freedom of ticketless traveling on most routes, a 2 day Tell Pass for your days in Lucerne plus a 4 day Regional-Pass Bernese Oberland would be easier. You'd only need additional tickets for your inbound and outbound rides, and for the few mountain rides that aren't fully covered by both regional passes.
I hope this helps you decide.