NEW YORK — “Monty Python’s Spamalot” hits the road March 7 with dates at the Colonial Theater in Boston.The Mike Nichols-helmed tuner nabbed the 2005 Tony for musical, and plays to soldout perfs on Broadway at the Shubert Theater. Producers report a current advance of more than $30 million, and they expect the $12 million tuner to return its entire capitalization early next year. “Spamalot” looks to be the next road behemoth after “Wicked,” which recently opened in the Windy City to full houses. The “Spamalot” engagement in Beantown runs March 7-April 15. From there, it goes to Chi’s Cadillac Palace Theater, April 18-June 4, and then on to D.C.’s National Theater, June 7-July 9. More national tour dates are to follow.