You don't challenge as an infringement on state's rights. States, as in sovereigns, don't have rights they have powers. The term "state's rights" just bothers me. People have rights, sovereigns have powers. The power of the sovereign is limited by the rights of the people.
States have the power to regulate everything and anything unless the subject is the exclusive domain of congress. Congress has the power to regulate that which the constitution says they can. The tenth amendment strikes me as a superfluous provision what it states is patently obvious from the reading of Article I sections 8-10.
You would challenge it on the basis that congress lacks the power to do so under the constitution. The problem with this argument is that congress' power under the commerce clause has been interpreted very broadly since the mid 1930's. Congress only has those powers enumerated under the constitution. The gun free school zone act and the PPACA are two of the few federal laws held to exceed congress' power under the commerce clause.
The GFSZA was an easy one for the court since the state already had such a law. Therefore the ruling wouldn't have much effect other than forcing offenders to be prosecuted in state court. The PPACA though not upheld under the commerce clause was upheld under the taxing power.
The supreme court has not been all that receptive to arguments that congress has exceeded its authority. The court often goes out of it's way to find a reason to find that congress was well within it's authority. Not that I particularly agree with the courts approach but it is well settled that they get to say what the constitution means.