With the exception of health club contracts, and the additional provision you mention, there is no general provision in Massachusetts that provides a cooling off period or allows consumers to cancel contracts.  You are correct regarding door to door sales contracts.  MA General Laws Chapter 93, Section 48 states in relevant part:

Section 48. A. An agreement providing for the sale or lease of goods, or the rendering of services, or both, primarily for personal, family or household purposes in excess of twenty-five dollars in value and which is consummated by a party thereto at a place other than the address of the seller or lessor, which may be his main office or branch thereof, may be canceled by the buyer for other than the seller’s or lessor’s breach, whether or not such agreement contains a provision for periodic payments or an extension of credit, provided the buyer, not later than midnight of the third business day following execution of the agreement, notifies the seller or lessor that he is canceling, and such cancellation shall be effective thereupon.

Similarly, MGL Chapter 93, Section 68D allows consumers to cancel contracts for credit repair services within 3 business days.  For more information or to post a question, visit our MA Consumer Law Discussion Forum.