4 Days in Murren in Juli help with itinerary

So many good posts and great responses to help plan between so much to do, so here is my tentative itinerary and request for input.

We will arrive Murren late in the afternoon of July 1st. We wont be getting started each day at dawn (I do have a 12 year old son who prefers late nights and late mornings on vacation) but we can get up early if any of these days need that. I am assuming up and breakfast finished between 9 and 10 AM. I have tried to piece this together using the great maps and timetables that many of you provided links to but don’t want to spend a lot of time back tracking which I think you folks can help me with and also are we planning to much for a day or am leaving a lot of time open.

Day 1: Mt Schilthorn, scenic trail Grutschalp- Murren, Gimmelwald

Day 2: Hike Mannlichen to Kleine Scheidegg, visit Wengen and Grindelwald, Pfingstegg and toboggan, perhaps trotti bikes

Day 3: Lauterbrunnen, walk or bike to the falls in the valley, then to Interlaken and St Beatus Cave

Day 4 : Meiringen, Aare Gorge, Reichenbach Falls. Would via Grindelwald be the preferred rout to Meiringen rather than through Interlaken?

I see others mention Harder Kulm. Would that fit into Day 3?

Is there time and logistics for Grindelwald to First and the Cliff Walk and perhaps mountain carts?

Any adjustments suggested to move things around? For example can St Beatus fit easily into Day 4 on the way back or perhaps Lautenbrunnen in Day 1?

Thanks much