With the greatest respect to Her Majesty, I don't understand why people want to view her closed coffin as they will queue for hours, maybe days, to see a coffin draped in a flag. So is it to show her Family how loved she was? I could understand that, but it is a lot of time and probably money, to spend to let the Royal Family know that - I think that I would rather write a letter of condolence to my choice of her Famy Members, and I would say at the end that they needn't reply, as I know that the Queen at least, always got her Ladies-in-Waiting to reply to all of her letters if she did not do so herself. By the way, if it was an open coffin, I personally would still not have wanted to go, but I suppose people could think that they have seen HM one more time, and could say a fond farewell to her.
As for the day of the funeral itself? If I was a lot younger and healthy, I would have gone to London if I could afford to spend several days away from home/work, and if I could get there in time to allow me to get a front row position. I would also have had to be able to book a room somewhere where I could get a shower etc - so I would have needed at least one other person with me to save our places - and I would have taken a very small tent (if they are allowed), or a very big umbrella, a camping chair that reclines, a warm sleeping bag, a pillow, an extra blanket, my kindle, a big flask that I could refill in the hotel room, etc.
Unless you go down there by probably Thursday OP, I don't think that you or your DD will have a chance to actually see The Procession, but I presume that the service will be played to the crowds through loud speakers, they might even have screens up; so if you and your DD want to go for
'the atmosphere', and maybe to be able to tell that you were in London on the day of the funeral, then yes go - it will be a day that will be kept in a digital form for many, many years, maybe hundreds of years, and you and your DD will be able to imagine your Great, Great, Great Grandchildren telling their DCren that they ancesters were there on the day!