Have seen may questions on driving to Jungfraujoch by other users. Having done it myself recently here is the experience. This is an answer to all those who wonder how far can they drive when visiting Jungfraujoch.
General driving is not permitted beyond Lauterbrunnen or Grindelwald, only people permitted are the local residents or essential services (construction, maintenance etc) so you would have to park at either of these 2 locations and catch a train from there to Kleine-Scheidegg where you change onto Jungfrau rail.
There is very little difference in ticket price if you take the train to Jungfraujoch from Interlaken or Grindelwald. I drove to Interlaken and parked the car at the train station where the full day parking charge was just CHF5 and found the parking very easily. Driving to Lauterbrunnen or Grindelwald is a possibility but the car park there are smaller and more expensive so you spend more money, time and petrol yet enjoying lesser.
So consider leaving your car at Interlaken and catch a train up which is quicker plus gives you beautiful views which you may not see while driving. Additionally train also allows you to do a full loop i.e go up via Lauterbrunnen and come down via Grindelwald or vice versa.
Hope this helps !!