Hi there Lupa. FWIW I am a ga pilot and flight instructor based out of Hanscom (KBED) but have been a regular pax on the airlines out of Boston Logan for over 20 years. Welcome to our great city. Here's my two cents worth.
FYI, they are building a parallel taxiway between Rwy 4L and 4R and this has necessitated numerous taxiway closures. All international arrivals (except Canada) usually go to Terminal E and Ground Control has you coordinate with Ramp control before entering that ramp.
The runway configuration at KBOS may sometimes be dictated on noise considerations as much as operational considerations. Massport the operator of the field & FAA try to keep the neighbors in the surrounding towns of Winthrop, East Boston, Chelsea and South Boston happy. The airport moves metal pretty well except when there is very strong NE or NW winds when delays mount as they're down to one runway 4R in NE winds (since they can only depart turboprops off 4L due to terrain). Rwy 33L in strong NW winds is the only runway usable if crosswinds prevent the use of Rwy 27. Rwy 33R is a joke and is virtually never used. They do have Rwy 14/32 which is a one way runway (Land 32, Dep 14) but I've never seen it used and I'm certain they'll not assign that one to an A340 :-)
Have seen some heavies request 15R for departure when other configurations are in use and they usually get their request after a prolonged holding in position. This does mess up the system and greatly increases the risk of a runway incursion hence the delay to allow for greater coordination between controllers. We've had a few close calls on departures from this runway.
The typical runway configurations are:
Dep: Rwy 22R/Landing: Rwy 27 and Rwy 22L (hold short 27). They can approve full length 22L on request but may want to know reasons for the request. Heavies often use 22L for departure.
Dep Rwy 9/Landing: Rwy 4R. In good visual conditions, they may have turboprops & RJs landing on 4L as well. I've even seen an occasional MD80, B737 or A320 land on 4L as well. Rwy 4R is the low vis runway with Cat IIIb capability.
Dep Rwy 27/Landing Rwy 33L. Have seen the heavies use 33L often in this configuration.
Dep Rwy 33L/Landing 33L: this configuration usually happens in winter months with strong and gusty winds out of NW.
Dep Rwy 9/Land 15R. Have seen some turboprops assigned ILS 15R circle to Rwy9.
Very late night if winds permit, the airport goes to a one way operation: Dep 15R land Rwy 33L .. but you won't have to worry about that unless you're a freight dog.
Hope that helps ..