Thank you all!
Re: castles -- we did do the Spiez castle last year and enjoyed it. Lots of interactive components, which is engaging for me. I was more curious about Thun, Oberhofen, and Hunegg Castles.
@Lola: My wife has to wear a post-op walking shoe on that foot. Hasn't been painful so far for her, but we haven't done much walking. I have a feeling uphill/flat, as long as terrain is stable will be fine, and that as you suggest, downhill/unstable will pose a greater problem. Also because it's not a boot, we want to avoid mud. Re: babies, we will be doing a front carrying pack, no stroller.
@Laurel: Thanks for posting about Switzerland Mobility. I do think Ballenberg, which we did two years ago, would be a good idea again.
@Dave A. - we actually haven't done any of those things. Are they all worth it with Murren as a base? I think you've convinced me to eliminate the St. Beatus caves. Are both those lakes swimmable? How touristy are they compared to Murren/Wengen? Overrun or not too bad?
@Maureen: So would you say Thun is worth the half day trip? Sounds that way! (Along with the other castles nearby)
@wanderweg: I think we were just remembering some parts as very narrow--following the restaurants en route to Schiltalp (I think that's what it's called) as you are leaving Allmendhubel. And so that's why we'd walk up from Murren towards Schiltalp (clockwise, I believe) towards Allmendhubel because even though it's uphill, it's mostly paved, no? You're right that the long walk around with the baby and wife's foot wouldn't be ideal. But maybe a short walk along the base of the lake -- or is it simply not worth it from Murren? I'll dm you, as well, as I know you're Murren-based.
Thanks, everyone, again!