Well first of all be aware that to earn a living playing rugby you have to go overseas. The highest level of play in the USA is the semi-pro "SuperLeague" clubs. But those Americans who do play professionally were (generally) scouted through the amateur clubs. Most men's college rugby in the USA is a club rather than a varsiety sport. Some of the stronger colleges which take rugby seriously (U. Cal. Berkeley, Brighan Young) can challenge the Division 1 or SuperLeague clubs, but generally club rugby is the higher level of play. But be a good enough college player in solid program and the better amateur clubs with contact you.