How strenuous is the hike? I understand it is 17 km (roughly 10 mi) and crosses 2 rivers. Someone said it take 14 hours. Is that because it is such a strenuous trail? Or does crossing the rivers take a lot of time? Or do you stop a lot to see the animals(best of the reasons I can think of). We did 9.4 miles in the mountains here in Montana last weekend with 1000 ft elevation gain in 6 hours. I was very tired by the end of the hike and my 68 y.o. husband (who wasn't the least bit tired) wonders if I can do the Sirena to Carate hike. I am 61 but not in nearly as good shape as he is.