I will be going to several different places on my trip in may I'm gonna give y'all a rough draft tel

I will be going to several different places on my trip in may I'm gonna give y'all a rough draft tell me what ya think, whether to much or not enough time between things let me know. Or if know of something else to add or take away.
For instance - you say arrive London 11:45 - is that by plane? From where? How long will it take to get into central London? And the sights you have listed will take more than a full day - never mind the later afternoon and evening that you will have.
Suggest you gets city maps and Tube/Metro maps and some idea of how long it takes to get from one place to another. Also use a MIchelin green guide to see how long it takes to visit a sight and actually see anything (you can't do the Tower of London in 30 minutes - it will take more like 4 hours - including waiting on line to get in - except it will probably be closed by the time you get there.
And you haven;t left enough time to get to any of the meetings listed. Arriving in Rome by air and making a meeting cheap europe travel at 7pm is going to take Superman - or a helicopter. (unless the meeting is at the airport).
On a few of your busier days, you might want to prioritizeand pick the two activities that mean the most to you, then make the rest of the activities "alternates," i.e. Day 1)top priorities are Tate Modern and Tower of London; if I have time, will do London Eye and Shakespeare exhibit.
First of all ifyou arrive at 11:45AM you will be very lucky if you get to your hotel by 2PM. 2:30 or 3:00 is more like it. After checking in and refreshing You might get a ride on the Eye, but definitely not Tate Modern, the Globe and the Tower. The Tower of London is not a 'walk by' - it takes a minimum of 3 hours.
When my spouse and I first started traveling, we would try to jam in four or five things a day. Now, we try to do two major things a day with lunch in between and no dinner. That way, you can take time to see stuff, stop in a cafe, rest your feet, and watch people.
As far as your Greece portion of the itinerary - it is doable but you don't have enough time to get a flavor of the country. The rest of the trip is way too overloaded with destinations. When posters share an itinerary and ask if it is too much, it indicates they already know the answer.
As others have pointed out, your plans for some days would require a time machine. In particular, reconsider Days 1, 14, 20 (unless you take an earlier train), and 21 (the train ride is at least 8 hours before you drop luggage at your hotel and continue to Schonbrunn on the Ubahn). I agree with the suggestion to drop a couple of destinations.
It won't really be that easy in 'real life'. You will have presumably pre-booked cheap europe travel all you flights and most of your train trips. What will you do w/ all those reservations once you find out you bit off more than is possible? (And IF you won't have pre-booked most of your transport, you will pay a HUGE amount of $$/ / )
Check the times of things. Days 20/21 - unless things are open late those days, you will only have a bit of time to walk around the outsides - an awful lot of time money spent traveling for very little sight seeing time. Actually, on many days you are spending more time on the train or bus than you are being someplace.
Day 14 is iffy for making a 7:00 meeting. It is fine to play some things cheap europe travel by ear, but it might be good to have a clear idea of the time involved getting to different places and how best to do it. Example: Oxford Cambridge on the same day - not a good combination logistically.