I tried reading it twice and then the third time I actually read it.
It helped that my brother was in rehab at the time and we (the fam) visited him for an "intensive weekend" (or whatever) which included an Al-Anon meeting or two. That experience going on in my life really dovetailed with large parts of the book, and I know I found the book more personally interesting as a result -- plus, relatable -- eh, you get what I'm saying.
In all honesty I don't think having a guidebook to a book is going to do anything but make it harder to plug into the actual book/experience of reading. It adds another layer of complexity and insists that The Book In Question is Deep and Must Be Explained - that it is Significant and Important and if you don't "get it," you should get it. Whatever it is, which is something vast and literary that spawns from glowing book reviews written by navel-gazers deep within the academy.
I would say if you are going to (try to) read Infinite Jest, don't approach it as a thing to be understood. Approach it like any other casual messy (just rather long) story. When you are done reading you will probably have a lot of unanswered questions that maybe could be resolved with a second read-through, but with well over 1000 pages, who's got that sort of time? So just look it up on wikipedia and find out what answers you want to know about the text, because lots of intellectual and academically "literate" people have analyzed and re-read the book to death and done all of that work making sense of it -- let their work work for you.
you're not an english professor you're a reader. infinite jest is just like any other book. if you can't get into it, put it down, shrug and walk away. infinite jest is on par with 50 shades of gray in that way imho. if it doesn't work for you it doesn't work for you and that's more on the book than it is on your intellect or ability to appreciate it or whatever. and if it doesn't work for you why slog through 1000 pages just because a lot of other people including a bunch of english-literature-mastubatory-canonical-library-dwllers who aren't paid very well but do enjoy agonizing over details say it is Brilliant.