Regarding Arneson, you can find documentaries online and books. Here are some other sources:
Rules for Middle Earth by Leonard Patt (~late 1970): https://playingattheworld.blogspot.com/2016/01/a-precursor-t...
Tolkien was reportedly mentioned in versions of Chainmail (Gygax's precursor to D&D) and OD&D (the rare, staple-bound ~prototype/MVP version predating the breakthrough editions, Basic and Advanced D&D), but after an IP dispute the Tolkien references were removed and Gygax repeatedly disclaimed any interest in or influence by Tolkien, despite obvious similarities. There are also articles Gygax wrote for late-1960s fanzine, Thangorodrim, where he openly adopts Tolkien material: https://archive.org/search.php?query=thangorodrim