You can also bypass the river crossing pretty easily, if it weren't filled in with gravel. You'd just take Basin road instead of Afton Road, which is one exit north of Afton Road on I-15. You'd miss the drive through the canyon, unfortunately, which is arguably one of the best parts of the entire trip. In reality, you could drive through the canyon all the way to the water crossing, then turn around and head back to Basin Road and take that back out. Many people who go back into the canyon take Basin Road instead of Afton Road, to avoid the water crossing.