1) Less and more than you think. Bank on at least one to two hours out of every four (that's about their sleep-wake cycle for the first couple months). Very little of it is hard if they're not sick, but the cycle is relentless.
2) Babies are very portable for the first 6 months or so b/c they're so oblivious to the world. Wake-up, change them, feed them, interact for a while, put them back to sleep for another 2 hours and they don't care what else you're doing. One parent having a full time job is easy, two is expensive and hard. Downtime is plentiful because of the frequent naps. Ditto for exercise as long as you're going one at a time while the other tends baby and unwinds.
Ironically, scheduling is much harder once the baby sleeps through the night, because at that age they're much more alert and aware during the day and therefore need a more rigid nap time routine. It gets a little better around 12-18 months when they go from two naps to one, and even better around 3-4 yrs when they drop the daytime nap and stay up all day.