I think on the water, the simple expedient of a little raft of 3 logs lashed together might get me to where I needed to go.
Clumsy, heavy and hard to paddle and steer but it would and has worked.
The bigger challenge would be the paleo effort to cut down the trees and dress the logs.
To this day, The Haida people and others in the Pacific Northwest create cedar boats some 40 - 60' in length.
Carved from single cedar logs, these boats are quite seaworthy.
It is known that the Haida raided and traded all down the Pacific west coast,
some claiming that they went as far south as Peru. (Peruvian potatoes are cultivated by First Nations Tlingit people in Alaska.)
Mungo Martin (Kwakwaka'Wakw) was said to have built more than 40 of those cedar boats.
Here in the interior, the boats were dug-outs carved from large Cottonwood logs.
The most recent one was completed in Prince George, BC (Nechako/Faser junction)about 2015 or so.
I don't remember if the First Nations people used fire or not.
Must be really hard to burn a fresh wet log.