Everyone should have used 2 days and I think you were all carrying 5 days emergencies as you were only going out for a 1 day out and back trip. Except Fisk, who is out of food.
I think the faster way across the river would be to find a tall enough tree close enough to the river and cut it down. That said the spells you are talking about would be dependent on the grow rate of the plant chosen. I just did some looking and the fast growing conifer can grow up to 3 feet a growing season (probably 8 months here). Verdant hand causes it to grow 100 times faster with a marginal success or 300 times faster with a critical success. The spell lasts 4 days for you so it would grow about 5 feet in 4 days. 15 feet if you manage a CS. Pretty fast really but not much use here. The figure spell which shapes it lasts longer than Verdant so you could shape direction of growth etc.