Need Advice Boston area

What he said!

I'm a she, but that's OK! :B

Any of the Logan Express buses will deliver your passenger to a station on the Rt 128/I-95 belt where there is ample room to maneuver a trailer. It cost less than $10. From there go north or south on Rt 128 to pick up the Mass Pike.

Nearly impossible to go anywhere around Boston proper with propane and a large TT.
You take Rt95 or Rt495 around Boston and have him Uber, taxi or bus to Framingham . Pick him up there and jump on Rt90

What he said!

It's not feasible to bring it to the airport. Two thoughts: have your friend take a taxi, the T or bus to a mutually agreed upon spot along the Rt. 128/95 corridor. You will avoid the city completely that way. Or, drop the trailer off somewhere near the Rt. 93/128/95 interchange, go into the city to get him/her, and then pick up the trailer and continue south. There are also "park and ride" facilities where you might be able to wait. Your friend can take the shuttle that goes there. The one in Framingham puts you in a good location to pick up I90.