I would recommend driving to BOOST/NSI because you will most likely want to leave New Port at some time, and besides most people will not have a vehicle. That means you can collect the toll money ($2) for crossing the bridge to New Port and you can get gas money.
1. There is no toll to get to Newport from Base. The Bridge you speak of is the Jamestown bridge and you only need to cross it to go towards the airport or Providence. You won't cross it daily or anything.
2. I wish I would have brought my bike. The weather was extremely nice May-July and it would have been nice to have it. Up to you though.
3. Don't sweat BOOST. It is easy... the academics are a little challenging because of the amount of material they go over in the short time, but everything is very very do-able.
4. The rules of BOOST might change this year because the Mst Sgt marine who ran it before has since retired so someone else is taking over. I will make a phone call to a chief I know who works there and ask him if anything is different (i.e- it is now more strict, seabag inspections and such). Otherwise, BOOST and NSI were both cake. Just go where they tell you, study, and be on-time and you will have ZERO problems. It's so easy a caveman can do it.
5. If you are married and thinking about bringing your family to BOOST don't listen to the nay-sayers and leave your family at home if you want them around, especially if you have kids. I wish I would have brought my family with me. 6 months without them was another deployment! It was also crappy watching the guys with families leave at the end of the day during BOOST/NSI. It is nice to not have to sit in the barracks full time and deal with the drama. Not to mention having a living room to kick back in. If anyone has any questions about BOOST/NSI/College transfer feel free to e-mail me and I will hook you up with my experiences. Congrats, good luck, and Ciao.
Kevin