"a bunch of really catchy songs stitched together to me"
Apt description, and this probably describes most 20 minute prog tracks. I can imagine that this must be maddening to some classical music buffs who are used to more logical musical links between sections. Pretty sure Trung has mentioned this (hope I don't regret bringing this up) but he seems to like a lot of prog so who knows? But yeah, most of Caravan's long pieces sound like a bunch of pop songs linked together (or even just riffs/instrumental motifs).
One of the main things that keeps most of "Supper's Ready" interesting to me is the lyrics. Even when the musical sections aren't particularly engaging, Gabriel's lyrics are generally among his best. I really do think he was a great lyricist when he was in Genesis- one of the best, actually.