We went part of a tour in a bus..sorry I did not pay attention to parking.

We had hired a private tour guide, so he drove us to both places. I would say maybe 10-15 minutes by car. We easily saw both in 4 hours. Parade grounds are yours to walk around alone. The main structure is still there and you are able to walk out onto the platform from where Hitler made his speeches. Not maintained and the concrete below is used for a drag race track. Interesting, as our guide showed us were the different colored concrete out front of the structure. It is how the soldiers were able to line up in such precision at the rallies. We really enjoy the Courtroom where the high-ranking Nazis were tried. Many other trials were held there as well. It is still the Nuremburg courthouse, so the Courtroom may be in use some days. If it is open, there are headphones talking you through the courtroom, the main trial etc. Excellent. Also the same jail where the Nazi were held is still in use, right out the back of the courthouse. People of Nuremburg are still sensitive of their role in Nazi Germany. In looking at brochures or asking about the War Museum, they will quickly point you to Nuremburg's other great art or cultural museums. I have been to Germany several times, as a German major in college, and Nuremburg is the only city which wants to avoid its past as much as they do. Beautiful city if you have an extra day or two. The main platz is full of cobblestones, stores, cafes, old beautiful churches and a great place to relax and people watch.

We were in a private car so didn't have to figure out the transportation to the courthouse. I checked my Rick Steve's GERMANY, and he says: "The building is a five-stop subway ride from the Hauptbahnhof. Take the U-1 subway line (direction: Furth Hardhohe) to Barenschanze, exit the station follwoing signs for Sielstrasse, and continue 200 yards along the main street (Further Strasse) to the huge court building, turning right at the corner with the tall signs showing the four national flags. It's at Barenschanzstrasse 72. Steves doesn't talk about the bus schedule or where you'd get a bus if you prefer that to the subway. Sorry; I'm clueless on this part. One caution: the courtroom itself is still in use on some weekdays. You're likely to have no problem getting inside the courtroom itself on a Saturday or Sunday; call about the weekday trial schedule no more than one week before you plan to visit; closed Tuesdays.

I would recommend the audio tour, it covers the history very well and lets you spend more time where you like. You can easily spend 3 or 4 hours here if you view all of the exhibits.

We found parking around the corner in a residential area.

I suppose you can contact the court administrator to see if they would extend the professional courtesy of providing your group with an official tour of the court room, which is a functioning court room during the week. Otherwise, you can wait a day to visit it on the weekend.

It is Barenschanze a 3/4 stops from the rail station.

Special hours for holidays in 2018 10 a.m. - 6 p.m.30 March (Good Friday) this is what it states on their website

I believe Court Room 600 is open on Mondays and Fridays because it is a functioning, working court room. As such, it is not open to tourists during the work week so you cannot go there to look the place over and take photos.

Yes, you can visit the courthouse without a guide.