The Jamesian sentence is not as wildly complex here as it is in later James works like The Golden Bowl or The Wings of the Dove. But still, he throws down some doozies that it takes us a while to find our way out of.
The almost overly formal style of writing is fun, though, because it provides a shocking contrast when he decides to insert a little joke or cutting remark. At other times, the writing is almost so grandiose and dramatic that we get the sense he's making fun of himself—or maybe just us. Like this:
The early Roman spring had filled the air with bloom and perfume, and the rugged surface of the Palatine was muffled with tender verdure. Daisy was strolling along the top of one of those great mounds of ruin that are embanked with mossy marble and paved with monumental inscriptions. It seemed to him that Rome had never been so lovely as just then. (2.208)
Nobody could take "tender verdure" or "mossy marble" too seriously. Just try saying "tender verdure" ten times fast. It's almost impossible.
But these descriptions are few and far between, as most of the novel is spunky dialogue between Winterbourne and the coquettish Daisy, or Winterbourne and his dowager-countess-like aunt.