Hello, If you do the private tour you have to meet at the Queen Victoria Statue which is in the park just sorta behind/side the sunken garden. I'm not sure there is much of a difference in terms of walking distance from gates to palace. Also, there are stairs involved inside going through the exhibition. Sorry for delayed response.

No refund. It was specifically stated on my ticket.

Leagrave station (platform 1) to Blackfriers.... Blackfriers underground (platform 1) to Kensington High Street (Circle line towards Edgware). You can plan your route on Google, just put Leagrave Station to Kemsington High Street Station in options will come up. We left Leagrave at 9.37am to get the Super saver day ticket which was about £24 approx return ticket. That covered trains and tubes.

With the current CoVid-19 pandemic, I am not sure it will be open by then. If it is open and it is safe for travel, it is worth a visit especially if you take the tour. Personally, we are holding off on any international travel until the Fall or next year.

Yes, you can see the outside of the palace no problem. You can get all the way up to the palace and I believe it’s even possible to get into the cafe for a drink and a bite to eat.

You can go to their website and purchase the ticket

Not sure, but I think they might be as many students in the area when I visited.