2 day plan: Geneva - Interlaken - Mt Titlis

Welcome to the forum, swiss-traveller! I think your plan is too ambitious on some points. You will manage to visit the Jungfraujoch on April 20 for example, but I think it's too much to do skydiving in the afternoon as well. I guess you have you to follow an introduction program and some exercises first before taking off, so the total trip may last longer than just a few hours in the afternoon. Please ask for details at skydive companies, such as Skydrive Interlaken or Swiss Helicopter. As for April 21: you will be able to get to Lucerne and return to Geneva the same day, but in that case I wouldn't visit the Titlis as the trip to and from Engelberg adds another 1,5 hours to your traveling time. Instead, pick a viewing point closer to Lucerne, such as Pilatus. You could make a great round trip via boat, cog train and cable car. Traveling times can be found through the timetable.

As for tickets and passes: the best option would be to buy a Swiss Half Fare Card for this weekend. Even if it's only two days, the 50% discounts offered by the Swiss Half Fare Card will be much cheaper than buying regular full-fare tickets. Details and purchase options can be found here.

Supersaver tickets are available for some town to town transfers, but not for all. You can't book them earlier than 14 days before traveling. Booking from India is possible, but not all credit cards are accepted. Widely used types such as Visa and Mastercard are. You can just try two weeks in advance and see what's available, and whether a supersaver ticket would be cheaper than a regular 50% discounted ticket. If you're already in Geneva, just get to the railway station there and ask for the options there. Mention that you'll have a Swiss Half Fare Card, as supersaver ticket prices will be even lower in that case.

Hi swiss-traveller. Glad I could help! I agree that Interlaken makes sense. Hotels near the railway station can be found here. As for weather: to be honest, yes, it can spoil your plans. But that's a risk all year long. Weather is unpredictable up in the mountains and may change rapidly, so it's very hard to say what circumstances will be like this April. It's wise to make some back-up plans in case weather is bad.

The Swiss Half Fare Card will very probably be cheaper than regular tickets. Just the trip to the Jungfraujoch in itself nearly justifies buying one. The 50% discounted rate provided by the Swiss Half Fare Card for Geneva-Interlaken is still cheaper than (or exactly as expensive as) the most economical supersaver ticket deals I found. Especially if you plan to make some further local trips as well, for which supersaver tickets aren't available, this is an economical solution. Note that the Swiss Half Fare Card also provides further discounts to the supersaver tickets rates.

I'm pretty sure that international Visa cards will work, especially at larger companies. Supermarkets and smaller organisations may not be able to use it though, so you should always carry some cash in Swiss Francs. To be sure, you can best ask Visa directly.