If you don't want to do that really serious hike between Mürren and Oeschinensee, then you can use public transportation.
The time table will give you the information that you need.
I entered Oeschinensee as my destination, and the timetable actualy includes the mountain restaurant by the lake.
or, you can use Kandersteg as a destination in the timetable, then allow 10 minutes or so to walk east to the cable way which has small cabins --4 people probably - and runs continuously during the day time. Nothing after late afternoon.
On a random day in July, the trip will take 2 hours and 8 minutes to Kandersteg. The timetable can show a destination of the restaurant at the lake, and claims an additional 17 minute walk to get there. It is distinctly up hill with 400 meters altitude change. I'd tend to take the cableway from the eastern edge of Kandersteg and then walk the path a bit over 1 km too the lake.
map.geo.admin.ch/?topic=ech&lang=en&bgLa yer=ch.swisstopo.pixel karte-farbe&layers=ch.bav.ha ltestellen-oev,ch.swisstopo.swiss tlm3d-wanderwege&X=149620.00 &Y=619400.00&zoom=6
That is a very good map.
I have turned on the hiking trails in the menu, as well as transport stops.
If you zoom out, you can see the trail to Mürren via Blumlisalp (1200 meters higher) which continues to Sefinafurrga, passed by Schilthorn and d escends to Mürren. Yellow trails are easy. Red trails are "mountain trails" and should only be undertaken with good boots or sturdy hiking shoes, hiking staffs, and suitable clothing for weather changes.
Note that there are no technical climbuing sections on the route . (The would be shown in blue).
What is your experience level as hikers?
Nice hikes near Wengen can be found here:
www.myswissalps.com/hi king, in particular scroll down to Männlichen - Kleine Scheidegg
Also, this may help you with hikes and Wengen:
When are you going? If it is the Fall, there may be constraints on any high altitude hikes.