I frequently get on sites like the Macintosh Garden from my Quadra 840AV using Netscape 4 (4.3.2, IIRC). It seems to work quite well if you don’t expect CSS, though it does get “broken pipe” errors if you try to follow an https link. (Not a surprise, it’s too old to have any encryption protocols in common with anything halfway current.) I have every expectation of using even older software when I get around to recapping my Classic II’s analogue board—16MHz on a 16-bit-wide system bus is pretty painful with any program unless you go super simplistic.