Best sites to explore between Basel & Lauterbrunnen ??

We had a very similar itinerary. We stopped in Bern for lunch and a nice walk around. The historical centre of Bern is amazing; there are practically no buildings less than 500 years old (as Bern has not had a war or fire since then).

Another thing you can do to use up another slice of time is to stop at the HUGE Coop store across the street from the Interlaken Ost train station. There's something there for everyone, from chocolates to dinner to fruits to t-shirts to electrical items. It entertained my teens.

Also, since I've done these hikes with my teens, I'll private mail you our dozen favorite hikes in the area. (Click on your name in upper right of page to read your private mail.) Others may request these maps and pics as well.

If it were me, I'd head straight to Lauterbrunnen, bring my luggage to the hotel desk to store until check-in time, and go explore Lauterbrunnen, Staubbach Falls, and other waterfalls along the Lauterbrunnen Valley.

Go straight to Lauterbrunnen since the alpine mountains is what you are there to see, put your car in the multi-storey car park, and do something. Don't waste that day watching the clock.

You want to make the most of the time available? Do so.

It sounds like you are renting a car (your previous post had you renting one in Bern) for this trip. Are you sure that using the train from Basel won't end up being - all together including dealing with getting and disposing of the car - cheaper, faster and much more scenic for all 5 of you?

@Darren: Thanks for your suggestion! Bern is definitely a possibility! Do you know if there is castle near there? That is one site that is lacking from our vacation.

@Shoe: Will definitely stop in the COOP store for some goodies! And thanks for the hikes, we will be taking some of those during our 4 days we have on the mountain. Any suggestions for sites off the mountain? I know you have been there a couple times.

@Linda: Unfortunately, no hotels for this family.

@ Nigel: Thanks for your pointers? I see you have followed my itinerary and questions I have previously posted. Unfortunately, when traveling in a bigger group train travel and passes can add up quickly. So thanks to many people who provided wise counsel and out of the box thinking, we were able to find transportation connections that came in under that price tag of taking the training all the way to our final destination, as well as outings we had planned. If you kindly re-read my post, I am actively looking for additional sites to see while in Switzerland so we are not just "watching the clock." But thanks for your two cents. ?

RK, I just replied to your PM, but now I see your comment "Do you know if there is castle near there? That is one site that is lacking from our vacation."
If you want castles, there are plenty, but how about a walled town?
Murten is near Bern, and ticks all the boxes. A small walled town on a lake. Not much to keep you interested for more than 2-4 hours. You could stop there for a late lunch.
You can walk on part of the walls - definitely a boys thing to do.
Some photos here: http://www.schweiz-foto.ch/Freiburg/Murten/Bilder.php

Have you ever climbed under a waterfall (Giessbach between Interlaken and Brienz) or seen wood carvers at work (Brienz) or been up a funicular to the actual Reichenbach Falls where the (some say fictional) Sherlock Holmes had his battle to the death with Moriarity (Meiringen)? Or considered a lake steamer ship to connect all of the above (train from Brienz to Meiringen, one of my favourite places)?

Or take a longer drive (if you prefer that's fine with me, I'm regularly there with my own car I drive from England) via Luzern instead of Bern from Basel to Interlaken and drive the Brünig Pass (make sure to avoid the tunnel default options as you approach them on that route after the ride past Alpnachstad or you will miss the great views. That Brünig Pass route is honestly far better on the panoramic cars of the railway as you go through the forests, up and down the cliffs, and see the lakes and waterfalls - the train is narrow gauge and is a rack railway (sometimes called cog-wheel) yet it runs every hour and costs the normal price for the distance; but the road journey is still very nice if you avoid the tunnels. Be aware that from Luzern all the way until Meiringen the highway is only one one lane in each direction with a solid line between the lanes so no passing.

@Chris: Thank you! That's the type of suggestion was I hoping to receive; something I'd never find in my neck of the woods, and a little different than what we'd experience on the mountains!