Yes, I have driven in Switzerland, twice, but the other dozen or so times I have taken trains, which I much prefer. Frankly, I think having a car WASTES time, trying to go thru center of the city traffic and trying to find parking. If you just get a general point to point ticket in Switz, you can take any train you want that day, so I don't see it as a set schedule. Also, I can relax/read a book on a train which I can't do while driving.
If I only had 2 days in Lauterbrunnen, here's what I would do:
Day 1: get started early. Is the weather clear? If so, immediately get a train up to Wengen, buy some breakfast/snacks at the Coop up the hill from the train station there, then head to the cable car station that connects Wengen to Mannlichen. At Mannlichen, pet some cows, then take the 2 hr trail heading toward the mountains. Best views in the world, in my opinion. Then take the train down from Kleine Scheidegg to Wengen to Lauterbrunnen.
Day 2 (or whichever is the cloudier day): take the cable car (station across road from train station) up to Grutschalp. Skip the train up there, but instead take the trail that roughly follows the tracks toward Murren. About 2 hours later, explore Murren, maybe take the funicular up to Allmendhubel, find the cable car station that goes down to Gimmelwald and Stechelberg, walk from Stechelberg to Trummelbach Falls, see them, and walk the valley back to Lauterbrunnen.
Will all the above cost some money? Yes, but absolutely worth it on a good day. You will NOT regret it.