Recommendations for a 2 week trip to France and Switzerland

Hello everyone! I’m planning a Spring 2026 Europe (yep way in advance) trip with my 70year old parents. I was hoping I can grab your recommendations and thoughts to see if my itinerary is feasible.

We plan to fly into Paris spend ~4days there, take the train to Lourdes for ~2days, then train over to Geneva and spend ~2 days. This is where I’m not sure what to do. We would love to visit Interlaken and spend ~4days there but should I cut that down and try to add Lucerne too? The last town would be Zurich and then we’ll fly out from there.

My husband and I are big on the outdoors and would love to get some hikes in. My parents are not huge walkers and happy to sit by a cafe and look out to the scenery. I’m trying to plan a trip that is a happy medium for all of us. I really appreciate any advice you have! Please let me know if you have any questions!