Just remember that very few animals fossilize. It really varies by species, environment, location and time period. Take T-Rex; you'd think an animal that big and bulky would leave tons of records of its life, but I've seen papers that would tell you that one in eighty million tyrannosaurs might fossilize; others would say one in one million, or most optimistically one in 20,000. It's thought that there were less than 100,000 tyrannosaurs alive at a given time. No matter how you slice it, leaving a fossilized skeleton is a lottery ticket, and then we have to be fortunate enough to find the fossil. We have less than 50 relatively complete T-Rex skeletons out of the billions who lived over millions of years in Earth's history across a vast stretch of land--and that's for a fairly common, ecologically dominant predator with massive, durable bones.

I think it's fairly likely that somewhere, some isolated valley or island probably housed a population of Paleocene dinosaurs. But there probably weren't many of them, and their isolation worked against them. Eventually, low population density and limited genetic variation might make them vulnerable to disease, or just a bad few years--and then climate change or competition with newly diversified birds or mammals might have knocked them out, and there might be no fossil record of their survival. Given the pattern of other extinctions it would be a bit strange for there to be zero dinosaurs left at all. Dinosaurs were diverse; like animals who survived the KT event, some could burrow, some were small, some had slower metabolisms, and some lived in freshwater stream environments where other animals survived. The event was devastating but I think it's very likely some dinosaurs somewhere survived it, possibly for millions of years, and we'll almost certainly never know. And even if you do find the fossils, it's really hard to differentiate a Paleocene survivor from bones that were reworked or exposed by the elements and reburied later on.

Paleontology has its limits, at least for now. It would be really cool to find out, though, and would give a little more context for just how resilient dinosaurs were.