Ben would like Willy to take after him, move to Alaska, take a chance, work outdoors, and become a true success.
Willy esteems and admires Ben and is tempted to do exactly what Ben suggests. However, Willy is persuaded by a more corporate version of the American Dream and he remains at home, with his family, attempting to work his way to partnership with his employers.
Ben represents both boldness and the achievement of wealth to Willy. These characteristics can be seen as an articulation of self and self-determination which eludes Willy, who is not in a position of self-determinacy or potential success. The fact that he commits suicide as a money making venture is a clear indication of Willy's lack of economic potency.
Willy's relationship to Ben, then, can be seen also as a representation of Willy's relationship to success (and failure).
Ben is the foil to Willy's character. He is wealthy, bold, and a ruthless business man. He is the epitome of a success story and living the American Dream. He acts as Willy's mentor. In fact, Willy hopes his boys will be like Ben. He is one of the few people who find incredible success without doing much work.
Willy is the common man. He feels he must be a good provider for his wife and wants his boys to think he is successful so they will be proud of him. He wants to see himself as a great salesman. The problem is: he doesn't have faith in himself. Weakness and self-doubt plague him.