Viking ships were designed to be beached for easy access to the shore. They wouldn't need an anchor.
Ragnar tells the assembled group of men that he wants to go to 'England.' England (as the name of the country) wasn't actually used until 927 when Athelstan conquered the Vikings of Northumbria.
Although the Lindisfarne raid is considered the start of the Viking raiding period, England was not an unknown land to the Vikings before this. They had been trading with Northumbria for many years before the raid.
After looting the abbey, two Vikings carry off a large chest of gold. Gold is an extremely heavy substance -- a cubic foot of it weighs over three-fifths of a ton. Even if the chest was only half full, two men could not hope to carry it.
When Rollo puts his foot up on the fire pit the sole of his boot is a machined rubber heel with modern stitched tread.