Since my family is still in Massachusetts, I was lucky enough to leave work early in May and then move home for a few weeks before coming to Cambridge. I was excited to return to Cambridge and MIT to start LGO, but one of MIT's big weaknesses is dealing with grad students who don't start in the fall. I wasn't worried about classes and my classmates this spring, I was worried about housing.
Housing is the primary weakness of this program. I will explain...
Cons: If you want to live on-campus, you enter a lottery for a FALL assignment (you'll only know if you got one at the end of May) and in the meantime you have to find a summer sublet, either on or off-campus. Unless you get a sublet before you find out your fall assignment and then those two buildings happen to match, you'll be moving during the break between summer and fall classes. Just plan on it. Also, you cannot have your furry friends live with you.
Pros: You can get furnished housing if you're single, if you're married and lucky you could live in a building literally right next to sloan. Whether you're married or single, MIT shuttles run past all the dorms from 6AM to 2AM and the housing office allows you to break you lease at any time if you have an academic reason (like our internship) with little penalty.
Cons: Leasing becomes both easier and harder with this option. It will probably be harder and more costly to break a lease, you will be further from campus and won't have shuttles. You'll need to arrange for LGO roommates over the course of two days during the admitted student open house weekend, pay a premium to live by yourself, or end up with random roommates. You might not have A/C in the summer (if that matters to you)...yes Boston/Cambridge is in the northeast but it can still get humid and hot sometimes.
Pros: You can live in the same place summer and fall (no move in August), you can get more space (especially if you live further from campus). If you sublet your place during your internship you may not have to move much at all. You can find a place that allows your pets, though those are still harder to find in Cambridge than people would like. The one good thing about starting in June is that if you do want to buy furniture when you get here, there's lots on Craigslist since most other people are moving out.
In order to figure out what my best course of action was for housing, earlier this spring, I opened up Visio and drew some flowcharts. That helped, but starting school in June makes things a mess.
I, personally, ended up with a furnished summer sublet right by the T (name for Boston subway) and then will be moving to on-campus furnished housing in the fall. I've got that extra move, but, overall am happy with my decision.