>>1
Normally I would love to, but to my everlasting shame I'm still working through SICP. Shhhh.
>>3
"Advanced" here is a bit vague. Best to check out the actual course website:
https://groups.csail.mit.edu/mac/users/gjs/6946/index.html
This subject awards G-LEVEL Graduate Credit, however the subject is appropriate for undergraduates who have taken the prerequisites. Undergraduates are welcome.
Prerequisites: 8.01, 18.03, programming experience
8.01 is introductory classical mechanics, i.e. the Newtonian mechanics that everyone has to take, and 18.03 is differential equations. I don't know how it is in the CS world, but in my real engineering major it was a basic requirement. So it is a graduate course, but with some relatively fundamental prerequisites. That said, I just took a look at the first few pages and I agree that it's dense. In that respect it looks like the second edition is a bit more gentle than the first edition that OP linked to:
https://mitpress.mit.edu/sites/default/files/titles/content/sicm_edition_2/book.html
I can't vouch for it personally, but for an introduction to the subject it might be worth checking out The Variational Principles of Mechanics by Cornelius Lanczos, which Sussman recommends at http://aurellem.org/thoughts/html/sussman-reading-list.html and which seems to be highly regarded.