Hello debbiedeb
You are probably refering to the Swiss Travel Pass.
Whether the Swiss Travel Pass is the best option? Yes, if you spent around CHF 75 per day on full fare tickets. Otherwise, the Swiss Half Fare Card and individual tickets might be a cheaper option. With so little info on your itinerary, no serious advice is possible.
No, the Swiss Travel Pass, as it has the word Swiss in its name, is solely valid on the Swiss rail network, as a consequence, it covers your travel from Lauterbrunnen to Basel SBB.
Kind regards,
Roland