I ran Boston last year targeting a 2:30 time (i came in with a PR of 2:24, but sme setbacks and injuries made a PR unlikely). I didn't end up running very well that day, I made some really basic mistakes and I think you could benefit from my rookie mistakes. Boston CAN be a fast course, but its difficult to run correctly. Dont let anyone disuade you, a ton of Pros have run their best marathons at Boston, including Ryan Hall, Meb Keflezghi, Scott Fauble (not to mention the obvious legends like Bill Rogers, Alberto Salazar, Dick Beardsley, Greg Meyer etc). If you are smart you can crush Boston. Here are some things I wish I did differently.
1) Seriously train on hills. Find routes in your local area with slightly more elevation change than the Boston course, and learn how to run them at an even EFFORT. Boston isn't a course that you should click off consistent 5:42 miles. Run all sorts of different paces, get comfortable converting any type of workout to an effort-based session on a hilly course.
2) Maybe once a week treat yourself to an ego-boosting flat, classic checking-your-splits type workout. It's important to know what 5:42 pace feels like, then in your hill workouts, if you are running 5:30 or 6:00 you can compare that to how MP should feel.
3) Consider running semi-regular downhill runs. Im from Utah, home of tons of downhill canyon marathons. The top guys are running fast long runs down canyons every weekend, that is the best way to callous the legs to the downhill pounding. Boston has a lot of downhill, the first 10k can beat you up, and mile 15-16 leading in to Newton can beat you up. Maybe you could do something like 10 miles at adjusted MP down hill, then some tempo Ks on rolling hills.
4) Don't try to bank time in the first half of the course. Seriously, don't do it. The best runners tend to run even 13.1 splits, or to even run the 2nd 13.1 a little faster. You should run through Wellesley feeling GOOD. You should get to the Newton Hills with plenty of fuel, you should get to the top of heartbreak hill ready to attack. In my Boston I spent everything I had to get UP heartbreak hill on pace, and I assumed that the downhill 10k into the City would just naturally flow. NOPE. you need to let the hills naturally roll, then muster everything you have to attack that last 10k.
5) run in as many inclement conditions as possible. Boston is notorious for bad weather, chances are pretty slim that you will get a perfect weather day. That is ok, you can PR on a day with sub-optimal weather, you just have to train yourself to not freak out if there is a little headwind or some rain. A lot of runners ruin their race by over-checking the weather forecast, they allow themselves to be defeated before the even line up. Realize that not everything is going to be perfect on race day, and practice telling yourself that it is ok.