Hi Toni, and welcome to MySwissAlps!
>> 2 people ... May 3-6, 2018 ... May 3 from Paris Gare de Lyon to Basel SBB (10:03 -13:26) Basel SBB - Interlaken OST - Lauterbrunnen ( base for 3nights ) I cannot find the departure time of Basel to Interlaken for May 3.
Are you using the Swiss Timetable?
Your train from Paris-Gare de Lyon will arrive in Basel on platform 9. There is a train leaving platform 10 (the other side of the same platform) for Interlaken Ost at 13:31, which you can probably catch.
If you miss that one, there are trains from Basel to Interlaken Ost every half hour at -31 and -59 minutes past the hour until well into the evening. Most are direct, others require a change at Spiez. Platform numbers vary for different departures, but most will be stated in the timetable, and all will be displayed on the departure boards at Basel.
>> And the ticket price is it the same or it changes depending on when you are booking it? I tried to check for Jan 29 and it is 34.30CHF ... But I think it is for Swiss residents with half fare card
Full fare for the route Basel-Lauterbrunnen is CHF 68.60. The fare of CHF 34.30 is in fact the half-price fare as you suspected.
Prices can sometimes vary slightly according to route taken, but you don't get a cheaper fare by buying your ticket early. In any case, you can't buy online more than a month in advance.
There are other tickets offering discounted travel for a particular service, or for a whole day, such as a Supersaver or Saver Day Pass (both with conditions attached). I won't go into details here if you are going to be using a Swiss Travel Pass.
>> Basel SBB to Lauterbrunnen is all free with Swiss travel pass, right?
>> May 4 lauterbrunnen - kleine scheidegg ... jungfraujoch ... Kleine Scheidigg ... Grindelwald ... Zweiluetschinen ... Lauterbrunnen ... the only ride we have to pay is from Kleine scheidegg to jungfraujoch with 25% discount?
Not quite. With a Swiss Travel Pass, you get free travel to Wengen or Grindelwald, then 25% discount for the journey onwards to Kleine Scheidegg and the Jungfraujoch.
>> No need to book in advance right because it will depend on the weather for that day which can only be known a day before?
Yes. Weather conditions and visibility can change rapidly in the alps, so weather forecasts more than 24-48 hours in advance are not generally reliable.
You can check the webcam to see what conditions are like before buying a ticket to go up:
Weather forecast Jungfrau
>> May 5 Schilthorn Going from Lauterbrunnen bus to Stechelberg - Cable car to Gimmelwald- change cablecar to Murren - change cable car to Birg- chage cable car to Schilthorn Coming back take same route and explore murren and gimmelwald ... All this trip is free with Swiss travel pass?
Yes. Instead of going back the same way, you could do a circuit as described here in rockoyster's post of Jan 27, 2018 - 12:26 AM:
The cable car from Lauterbrunnen to Grütschalp is closed between 30 April and 4 May, but that won't affect you if you are planning this trip for 5 May.
>> May 6 Going to Domodossola Train from Lauterbrunnen - Interlaken OST - change train to Spiez - change train to Brig - change train to Domodossola ... Is this trip all free with Swiss travel pass?
Yes. You could make it more scenic by putting "via Kandersteg" into your timetable search. Doing this means you will see some lovely scenery instead of travelling underneath it in a long tunnel. If the departure times suited, you could also do the Brig-Domodossola sector by PostBus over the Simplon Pass, which is a wonderful trip.
If you are interested, I have written about both these trips (and included photos) in my posts titled
- Meiringen to Saas-Fee (first half of the post)
- Saas-Fee to Locarno (starting from the third paragraph)
>> Because in the image i have downloaded there are red broken lines from Frutigen to visp and from Brig to Iselle di Trasquera. Does it mean 50% off or just passing thru tunnels? Image attached.
Those are just tunnels, and those routes are free with the Swiss Travel Pass.
>> Alternate trips for bad weather is Lake Thun and Lake Brienz Cruise which is also free with Swiss travel pass right?
Have a great trip!