Memorial Drive and Storrow Drive both have low bridges that frequently snag trucks. So the best route for a truck to the Hyatt Regency Cambridge hotel from the Interstates appears to be:
If you're coming from North or South of Boston, take I-93 to the Mass Pike and then follow the Mass Pike directions. The Mass Pike toll for a 24' truck (two axles) is $1.25 from I-93 to exit 20.