According to BOB, no. They can't get two adapters on there and have the whole thing fit through a standard width door (32" or less). If you want this for the car/grocery store/quick trip, then I would go with something else that will hold the infant seats. This is a big stroller for errands. But if you want it for long walks/jogs/theme-park type trips, then you can use a head positioner (I used one of those buckwheat neck pillows to keep my little guy's head positioned) while the babies are little to keep their heads steady, and after 6-8 weeks or so, they'll be fine just in the seats if you aren't off-roading or going at more than a brisk walk. You can start jogging with them in there around 5 months.
42" would probably have a hard time in this stroller with the canopies retracted. The material on the canopies tend to bunch up above the child's head when they are not in use. The folds of the canopies fabric hang down into the toddler's head space. Your toddler should fit in if the canopies are fully extended, however...but you should be aware that you will have to have the canopies extanded all the time. This may or may not be a big deal for you. As an aside, if you truly want to use this stroller for "jogging", I would strongly recommend not getting this stroller and instead getting a fixed wheel stroller. I have tried running with this, and even with the micro adjustment for the fixed wheel option on this stroller, I find it always pulls slightly left or right. I prefer a true fixed-wheel stroller for actual running. The above comments aside, I'm very happy with the quality, ease of use, and light weight construction and features of this stroller. Although I don't use it for running anymore, I would purchase it again...it is my favorite stroller for general, every day use.
It is not difficult for my toddler as she had plenty of room to just crawls underneath the snack tray to get in and out she's 26 months. She loves being independent and helping herself in and out. Otherwise you would need to lift your toddler in and out as the snack tray stays stationary on the stroller once installed.
My husband said you need a bike pump with a "schraeder valve" not a "presta valve". We got an awesome bike pump for $20 at Walmart. It has both. I have to air my tires up about one a week. The more air the smoother the ride.