Besides being long, I didn't find "The Recognitions" exceedingly difficult. I was occasionally lost as to which character was speaking/being described, but the characters were mostly distinct enough to reason out. Pynchon's penchant for stringing along train-of-thought can be a bit more challenging. But, I definitely felt some proto-Pynchon vibes with Gaddis' writing.
That's a good assessment. I think my difficulty stemmed more from knowing that my Father could extract quite a bit from the text--especially since he is the son of a pastor/read the KJB at age 4 and could quote scripture to me seemingly at random. He is also the most interested out of my social group in art history, and is an english professor. Right up his alley!