You are more well-read than I am :)

The first book that you mentioned that I had already read was Tristram Shandy (what a fun book!). I don't recall where in history that lies in comparison to Ulysses as I honestly just read for fun and don't bother to remember simple things like dates or sometimes even author's names.

The Pinchon book was indeed Gravity's Rainbow. It was easier to follow from paragraph to paragraph but it still left one either skipping to Google quite often or left with a vague feeling of having missed most of it.

Uris and Michener though? Maybe we should reassess what the 20th century had to offer somewhere in the 22nd century.

I can't rattle off an entire list of the Western Canon off of the top of my head but, as it happens, I happen to have The Great Conversation, Vol. 1 sitting here next to me.

I see rather a lot of it that I'd consider very readable or accessible. The Greeks are readable, even fun. I don't know about the scientists of the Middle Ages, Copernicus and Kepler and etc. but I've St. Thomas Aquinas and didn't have any trouble at all. Dante we covered. Nobody can read original Chaucer but a translation is fine. Machiavelli is fun to read. Hobbes was a total chore and a bore, at least Leviathan was and I presume he didn't lose his religion before he wrote the rest of it. I don't know about Rabelais or Montaigne yet. Shakespeare is difficult for many but if you can get into the flow a lot of his stuff is really funny. Cervantes was hilarious. Descartes is no special challenge. After Milton we are into the second scientific Renaissance with Pascal, Newton, Locke and so on but after them we are right back to fun stuff like Swift, Sterne (found Tristram Shandy!)... oh, then it gets tough again... Rousseau, Adam Smith, Gibbon, Kant, Hamilton, Mill... blegh, I guess it's the history of the West rather than the fun history of the West. Anyways, there's a few after that and then it wraps with Freud.

Considering this was put together in the 50s, they knew about Joyce but neglected to include him. A whole bunch of concerned, University types didn't think middle America was quite ready for, quite required, James Joyce in their voluntary, advanced education. And I sure wouldn't want to be on the hook for updating the list next time. I know what I like but I won't make a recommendation unless asked.