Tentative England trip schedule

I’ve been reading and thinking away and think I have a basic schedule for my English pilgrimage:

Nov. 21-28th -- Cambridge with a possible day trip to Ely Cathedral
Nov. 28-Dec 2nd -- Oxford
Dec 2-12 or 14th -- London with a day trip to Canterbury

I'm going to try to get tickets to the Dec 2nd Kings College Choir concert at St. John's Smith Square and perhaps the Dec 13th New College Choir concert at Christchurch Spitalfields. I also will probably try to get tickets to the St. Johns Cambridge Advent service. (If getting any of these tickets is a pipe dream, let me know so I can adjust my schedule.)

Again, advice is welcome. Very early booking for some things would be wise I suspect. So I may start with that next week.