Same here :-( I would need a 1000 years to learn all the things and work on all the projects I would like to. Since I only have 50 years or so left (if I am lucky) on this 3rd rock from the Sun, I will have to choose the top 2% of cool things on my long list and stick to those...
I've a print copy of this, the content is quite good but rather marred by the annoying typsetting everything is all jammed in right up to the marigns (something which is sadly true across this whole series of great books).
The problems however are absolutely fantastic, a great mix of computational and theoretical which go from half an hours fun to really unanswered problems. Fun fun fun! I highly recommend trying them and referring to the text as needed.
Dirac said, “follow mathematical idea wherever it leads”. When I first opened ths book years ago, unpublished draft then, I just skimmed the ToC, checked a few problems and then to my horror encountered that interesting approach to restricted three–body problem (nicely wrapped as the “Jupiter” problem in the book). I was horrified because I had a lead on that too… and there – it's all in textbooks. That situation allowed no relaxed wackiness in my thinking about it anymore, I had to formulate my thoughts. ‘I need more math’, I thought. When I finally digged out of that rabbit hole I found myself learned in dynamical systems, ergodic theory, harmonic analysis, spectral theory, operator algebras, homology, algebraic topology, and constructive renormalization, and in numerical methods, symbolic dynamics, symbolic algebra, Grobner bases and group cohomology and applied algebraic geometry, and then Hopf algebra of Connes–Kreimer computable renormalization and, uh, followed Connes the way up to motivic integration… (ok. ok. I'm done enumerating now) at which point I lost all interest in physics and turned mathematician.
All that not to mention intersection of algebra and topology of statistical mechanics with coding theory and infromation theory which led me to machine learning (which is just statistics btw).
I'm unsure what the moral is. That was not healthy. (OTOH, mathematicians have high life expectancy, routinely living up to 90, gauging from AMS Notices obituareis).
Stat mech is basically the math of 'complex systems'. Evolution, neural processes, economics --- it's all coming out as stat mech in one way or another. Thus familiarity with stat mech is important if you have any interest in these areas.