Having re-read the original post more closely than I obviously did the first time, I infer that you're considering a true one-day ski visit, i.e., you don't plan to stay at the resort overnight. In which case, if you go to Wengen, you might want to know that you may not end up visiting the village of Wengen at all, save a brief stop on the train. To stay overnight, you have to take the train half way up the mountain to Wengen, but if you're only going to ski, you'll want to stay on the train at the Wengen stop and continue on up to the top of the mountain, to a stop called Kleine Scheidegg. If you don't get off at Kleine Scheidegg, you can stay on the train all the way down the other side of the mountain to another, larger valley town with cars, called Grindelwald.

If you will need to rent skis/boots, you might want to check and see if rentals are available at Kleine Scheidegg. I don't remember a rental shop there, but I wasn't looking for one. If not, and if you need rentals, you'll need to stop in Wengen to rent your equipment before continuing to Kleine Scheidegg.

And so it occurs to me that if you'll be driving, and if you need rentals, you might want to consider going to Grindelwald, renting your equipment there, and taking the train to Kleine Scheidegg from Grindelwald. That said, though, the view up the valley at Lauterbrunnen (on the Wengen side of the mountain) is much more spectacular than from Grindelwald, including a very dramatic waterfall that seems almost to pour right into the town of Lauterbrunnen in the summer, and the views on the way up to Kleine Scheidegg are better on the Wengen side too.

Just something to consider.

Man, I wish I were going, too.