Hmmm... The paperwork for filing for short term disability is always more of a hassle than you think it will be, and the deadline will sneak up on you.
Ask for the maximum amount of time off that you can. Maybe more. You can always come back earlier (yeah, right!), but it's hard to ask for more time once you're out.
You probably won't be able to get as much done in your "time off" than you think you will.
Be prepared to change your mind about whatever daycare you have selected. I visited several places when I was pregnant with my first and was impressed with how well they seemed to know babies, and I didn't see any problems. But a month after the kid was born, I went back and falt COMPLETELY different, as I thought to myself "What! They're bottle-propping a 3 month old! Somebody pick up that baby crying over there! For heavens sake, can't anyone here console a crying baby? It doesn't take two hands to wipe a counter." In fact, with both of my children, I changed my mind at the last minute.
If you have a little extra room in your house, at least look into the cost for an Au Pair. When I came back from maternity leave, I had no vacation days available, and everytime the baby was even a little bit sick, I had to take an unpaid day and it was an administrative hassle. And getting all those bottles cleaned and boxed, waking the baby up early to get them off to daycare on your way into work. It's a lot of hassle, and having someone in your home to watch JUST YOUR BABY can be reassuring, if you can get used to the idea of giving up some privacy. (Note, I haven't gone the Au Pair route myself, but I recognize now that there are definite benefits, so at least consider it for the first year or two.)
All Montessori schools are not equal. But once your child is old enough for a toddler program at a GOOD Montessori, I highly recommend that over other daycares, even the fancy Creme de la Creme and Goddard ones, and certainly over the "educational" ones like Primrose. They really teach toddlers so many practical, useful skills - my second child is on one now, and he's so much more capable in so many ways. (Montessori teaches self-care stuff like, being able to wipe your own nose, do your oen buttons, put on your own jacket, pour your own milk, clean up spilled milk, set the table and make yourself a bowl of cereal. My older son that was at creme learned to recite the months of the year, even though it was years before he had a good concept of how long "five minutes" really was.)
Oh - here's a GOOD one: Talk to your employer now about what you will need to pump when you return to work. And don't take "the employee bathroom" for an answer. Or even "you can use my office." I was pretty vocal about this, and it's not a topic that most men are comfortable talking about, so they tried to find a quick solution rather than have to hear details. As a result, my workplace now has a small, windowless conference room with a table, two chairs, electic outlet, and phone. (It still has to be usable for other purposes. Oh, and they have a small "library" of technical books.) The door didn't have a lock, so I bought one of those bars that you can jam against the handle - you know the anti-theft ones you see 'em at Home Depot. I even got them to reimburse me, and it stays in that room. So far, three other returning moms have been able to use that room.
I was a bit of a pain about this, but it has made it soooo much easier for other women at my work. Just one year before my little crusade, a co-worker (much less assertive) used a stall in the ladies restroom. NOT FUN. Especially when you want everything to be... clean and safe.
And finally, if your work and your job aren't close, try to get a daycare close to your home rather than close to your work. SERIOUSLY. There will be a few times it's a hassle, like when your kid gets sick or maybe gets a minor injury, but it's worth it. The plan to take breaks from work to visit your baby usually doesn't pan out for very long, especially when they are a little older. Once they see mom, they do NOT want you to leave. And if they're close to your work, you may have to battle rush hour traffic with a baby in the backseat, one that may not be happy. Also, if you stay there for a while, you'll probably make good friends with the other families. If it's close to home, it makes it easier for playdates, birthday parties, and, hopefully, trading babysitting with other families so you can have a date with your husband without spending a fortune on a sitter. If you are VERY lucky, the playdates will gradually evolve into grown-up time, too. Now that my oldest is 5, the playdates that he has with his very oldest friend (they met at 3 months in the infant room) involve the kids playing more or less independently while the grown ups have wine or margaritas, a nice dinner together and sit around the firepit watching the fireflies come out. It's usually so pleasant that we end up keeping the kids up way too late. You know all those friends that you haven't seen since they had kids? You'll probably start seeing them again. It's not that your social life ends - it just morphs.