I don't quite get the rules on boarding and charging, but apart from that it's not too bad.
There's a fine line between the two..
Charging can be best described as
Rule 41 of the NHL rule book dictates that charging "shall mean the actions of a player or goalkeeper who, as a result of distance travelled, shall violently check an opponent in any manner. A 'charge' may be the result of a check into the boards, into the goal frame or in open ice.
http://en.wikipedia.org/wiki/Charging_(ice_hockey)
Boarding is as follows
when an offending player violently pushes or checks an opposing player into the boards of the hockey rink. The boarding call is quite often a major penalty due to the likelihood of injury sustained by the player who was boarded, and officials have the discretion to call a game misconduct on the offending player. However, if no injury is sustained, then a minor penalty will be called.
http://en.wikipedia.org/wiki/Boarding_(ice_hockey)
It's hard as they keep adjusting the rules due to the speed of the game.. Hockey is the fastest game in the world played by man without a machine.. Improvements in gear and body mass has caused the league to alter some of these rules..