I agree with James that we are likely to see "glorious pomp," etc., but a much shorter, more telegenic ceremony. I also expect there to be some sort of ecumenical service and ceremony in Westminster Hall at Parliament. There has been a lot of work done quietly over the past twenty years or so by various academics and think tanks on how to modernise the monarchy, starting with the Fenian Society's commission on reforming the monarchy, which proposed reforms to the succession and royal marriage laws which were eventually adopted almost to the tee.

A group of academics a couple years ago proposed extensive proposals for modifying the accession process so that the King would still hit the required parts like swearing to uphold the rights of the Church of Scotland, but it would be put in a context which stressed the secular role of the monarch as a unifying figure for the entire UK and Commonwealth. Their proposals were also followed in some cases down to virtually the exact wording of the King's statements. Even more such work has been done about modernising the coronation while retaining the traditional elements. I would not be surprised if all of those articles have been poured over by the King and his advisors and will be used to shape a ceremony that seems ancient but is largely a modern interpretation thereof.

Most of this (the Succession to the Crown Act being the exception because it is a statute) was done without any acknowledgement or announcement of how it was being modified. They just did. This was the genius of the reign of Elizabeth II going back to the Duke of Edinburgh's work on her coronation and the way in which Lord Altrincham's controversial criticisms of the Queen and her Court in his 1957 article ultimately, without any public acknowledgement, were eventually largely all addressed and acted on.