Possibly a thing made for British people but I did it today with my wife. Joined 06:30 this morning and viewed the casket exactly 12 hours later. Quite a moving and powerful experience in Westminster Hall. Missed the children standing guard by 30 mins but did get to see a guard change happen as we entered. The queue itself was a big part of the experience and overall time went faster than you expected. Some bits dragged at the time and it was pretty chilly with the wind and in the shade for a lot of the time. Not sure I'd want to overnight it. Plenty of loos and drink/food places along the way. The route is anyway one of our favourite walks in London. Made some new besties and everyone was in good spirits including police from all over England and Wales. Legs and back ached a bit by the end but we were both glad we made the effort. I would say it is a very white queue which I found a bit surprising.