"rambling stoner conversation". Lol, you've clearly made it to Ken Erdedy's section, which is literally that. That's a brief passage in the book, and honestly one of the hardest parts to read.

I'd say there's a lot of groundwork laid in the first 60 - 100 pages or so. After that, I honestly don't think it would be harmful to cherry pick interesting passages from the book. You could research interesting sections of the novel and target those for a first pass read through, then maybe later read it sequentially. There aren't really plot spoilers as the book is somewhat plotless.

Even still, I'd recommend the first read through be sequential. My first read through was, but I also skipped around a little bit. My favourite thing about DFW is his writing style. Also might help to whet your appetite for his voice by reading something like "A Supposedly Fun Thing I'll Never Do Again", which is a hilarious anecdote and commentary about his trip aboard a cruise liner.

In general, I'd say the best advice is to free yourself from the burden of 'understanding' the novel on your first read through and just enjoy the chaos. Besides, there is so much ambiguity in the novel that, even if you do crystallize some understanding, there's likely many alternative interpretations. That's where the re-reads get really fun.