The safest way to cross this river is to make passage with the Ferryman. His real name is only known to a few who live within the mountain itself, and as such he is known outside only as "the Ferryman". He can be summoned by a bell. Beware about haggling with him over the price that he gives you. Even if that price differs from that advertised by his own notice, his lack of patience with outsiders is such that he may decline to accept your trade at all.
He is also a Wererat.