Switzerland with young kids

[Danceshakemove]

DC will be 6 years and almost 4 years old. We would like to be in the mountains to walk and explore (kids are well versed in spending time in the mountains and can walk up to 4 hours a day happily). Ideally we would like to do it as cheap as possible (for Switzerland anyway!) so would go for airbnb or camping (we have our own tent) or cabins. Could anyone recommend anywhere or any walking routes? It would be good to have a few play parks along the way or if anyone has discovered hidden gems for kids. All info and advice would be great. We dont have a set budget but the less money the better, we're happy to cook etc

Switzerland is expensive, no matter how you do it. Some itinerary suggestions below, the Grand tour, and camp sites along the way.

I have camped in summertime, near Interlaken and the campsite was excellent. it’s a stunning country and the Alps in summer are amazing with so much to do with kids.

https://www.myswitzerland.com/en-ch/experiences/experience-tour/car-motorcycle-grand-tour/highlights-search/

https://www.myswitzerland.com/en-ch/accommodations/other-types-of-accommodations/campings-search/-/grand-tour-of-switzerland/

packedagain.com/family-hotels-in-switzerland-with-kids/

Engelberg is lovely and there’s a campsite in the town which also has a small pool that you can use. You can go up in a range of directions (I reckon you could fill a week easily). On the Brunni side there is the more fun family stuff, but also lakes to walk around/play at/canoe on.
Switzerland is not cheap for food even if you’re cooking your own. We usually self cater and do a supermarket shop in France/Germany (depending on route) for non-perishables including drinks. Make sure you take packed lunches.
HOWEVER I would also have one day where you find yourselves a grillplatz and barbecue sausages for your lunch!
From Engelberg you can also go into luzern - transport museum there is brilliant for children.

Camping Jungfrau in Lauterbrunnen, access to mountain railways and lifts to Muerren and Wengen, with Interlaken and Schynigge Platte train and alpine gardens nearby
https://www.landal.com/parks/vierwaldstattersee#filter:eyJzIjoiMyJ9 near Lucerne
Resort Walensee about an hour from Zurich with access to skilifts at Flumserberg and a lake