OK this is crazy but maybe getting polynesian don't stop navigating when they reach Rapa nui (around S. VI-VIII) and continue his navigation until reach the Galapagos(around 3.470 km- 2561 mi) Which are Closer than America Proper and Closer Than Papete, is posible that the colonization of Rapanui come from the polynesian colony of the Islands Pitcairn, but for he sake os this POD, we say that the Polynesian could Reach the Galapagos around X Century, in middle of the classic era of the americans civilizations, this regrettably will cause decimation of the galapagos fauna, but i digress, Ok with a Polynesian culture in the galapagos they are in perfect position to connect by Sea thes nazca, wari and moche cultures of peru , the mayan culture or their descendents,the mixtecas zapotecas, mexicas, in Mesoamerica,this because the connection by land is extremely difficult even now (https://en.wikipedia.org/wiki/Darién_Gap) an help to connect and make he civilizations more complex, and they bring Chickens and pigs, maye they could help in creating plagues and give enough plague treatment knowledge to the more complex cultures,with the knowledge of good boatbuilding and open waters navigation, we could see that the caribbean flourish as a information and trade highway as a more "open" mediterranean sea, with this we could maybe will see an early bronze age civilization emerge in time of the columbian exchange, it´s even posibble we get a literate society, the olmec and mayas have and alphabet but not the incas, the peruvian civilization have superior metallurgy than the mesoamerican civilizations, and a better Agricultural package (potato, amaranth, quinoa,kañiwa, tarwi, pajuro Beans (https://en.wikipedia.org/wiki/Erythrina_edulis / https://www.concienciatv.gob.ve/blog/conoce-chachafruto),Oxalis tuberosa, ollacos(https://en.wikipedia.org/wiki/Ullucus) , mashwa(https://en.wikipedia.org/wiki/Tropaeolum_tuberosum) , Maca(https://es.wikipedia.org/wiki/Lepidium_meyenii), sweet potato,and domestic animals, llamas, alpacas. In mesoamerica we get the wheel, the three sisters sistem, cassava, the tomato, avocado,and turkeys as domesticated animal, and not much more as staples foods, be get more spices in mesoamerica, cacao, chiles, vanilla, maguey, and tropical fruits, so the trade is posible and desirable, plus the ideas and knowdelage trade as we see a good polynesian thalassocracy in america based around the galapagos and that could extend to the caribbean we get a more connected america and a america in better shape in time of the european contact, the gap are smaller between an early bronze civilization and europe than what we got in OTL