Certainly, a lot of different themes can be extracted from this one passage, but the one I focused on in my book was "friends." This passage in particular refers to Dean Moriarty (real-life Kerouac friend Neal Cassady) and Carlo Marx (real-life Kerouac friend Allen Ginsberg*).
The Kerouaction? Look to the company you keep as friends. Are they passionate about life or complacent? Unpredictable or boring? Do they make you feel more alive when you're with them or are they energy vampires who drain your life essence?
Reevaluate who you spend time with, and make sure that your choices in this regard enrich you and enhance your mental and physical well-being. This sounds judgmental, and perhaps it is, but the practical truth is that the people you hang out with affect your quality of life. Crystal and I know someone who we appreciate in a lot of ways but who is toxic for us to be around. So we act accordingly and never hang out with that person. We'll say "Hi" on the street, but we don't socialize beyond that. It's not "healthy" for us to do otherwise. On the other hand, we have another friend who we hang out with and probably get judged by others for doing so because this person is very much like Kerouac describes and doesn't ascribe to many of the current social norms. To which we say: Get over it. We'll choose who we hang out with and you do the same.
If someone brings out the best in you or makes you happy about life or challenges you in a good way, spend time with them! And vice versa. But love them anyway. That's how to kick the judgment trap. Being "nonjudgmental" doesn't mean you have to be a doormat and spend your life doing things that don't meet your own needs. It means being compassionate toward all sentient beings, extending them empathy. You can do that by connecting with the common human needs that underlie the strategies they use to meet those needs. As Jack says in The Dharma Bums, "MAY YOU USE THE DIAMONDCUTTER OF MERCY."
In conclusion, I'll leave you with a quote from Mary Oliver's amazing poem, "The Summer Day":
Tell me, what is it you plan to do with your one wild and precious life?**
Hopefully, you'll choose your friends wisely.
P.S. By the way, I think "mad to live" is an excellent idea for a tattoo. The only question is: Where to place it?
* Horror of horrors: I just realized I spelled Ginsberg as Ginsburg in this entry of my book. It's a typo I missed and no one has pointed it out in three years! Sorry, Allen.
**Horror of horrors #2: I just realized that I misquoted Oliver in this entry in the book, and, again, no one has called me on it. Sorry, Mary.