London pedestrian advice needed
 

I was wondering if any London experts out there could help me with 2 walking questions. If one were walking eastward along the south side of Hyde Park, approaching Hyde Park Corner, how would one best get across to Constitution Hill? Are there underground "subways" to get across the heavy traffic? Also, at the end of Constitution Hill, when one reaches the area in front of Buckingham Palace, how can one get across to the Queen Victoria Memorial? Is it just a question of dodging through the traffic that whips around the circle, or again, is there some sort of subway that will allow folks to reach the monument safely? I'm leading a group of students on this particular walk, and it would be good to know what I'm doing. Thanks!

from Hyde Park to Wellington Arch and then into the corner of green Park, there are a series of undeground tunnels.
There is a path in green Park that runs parallel with Constitution Hill and would be more pleasant that along the roadside. There are pedestrian lights linking the front of the palace and the memorial- this is the more dangerous part as the walk. But not horrible.
(toilet options are at hyde park near the tube/subway tunnel. The tiolets in Green Park at the "top" by Green Park Tube station. Don't be fooled by the signs in the park! Also there is a playground in St James accross from wellington barracks that has kids' toilets.)

The intersection around the Queen Victoria memorial is no longer a traffic circle.

Thanks for the help. Knowing that there are traffic lights to get us across to the Queen Victoria memorial certainly lowers my stress level. I appreciate the guidance.

I was down in that area today and one of the tunnels is GONE! You now must use the pedestrian crossings from Wellington Arch onto Constitution Hill or into green Park. It's really weird that they've completely filled in the tunnels and you must now cross at two points to get over towards Buckingham Palace. The lights have not yet been retimed, so you must cross half way and then wait for the other set of lights to change. Hope you see this before the trip.