M.F.
If you want to have any hope of feeding dinner to your family, use a crockpot!
Also, if your older child is already in full time childcare, don't be tempted to take her out while you're at home on maternity leave. Keeping her in childcare is the best way to keep her routines the same, and you will need the break. You may take her down to part time, but I wouldn't drop it completely.
Playpens and cribs are your friend. There will be times when you have to put your toddler in a safe place so you can tend to the new baby. She may scream like crazy at being "banished" but it's only temporary, and it's better than having her play in the toilet while you feed the baby. You may also have to do the opposite -- put the baby (again, screaming) somewhere safe while you tend to the toddler.
I wouldn't give in too much to the desire to separate the kids. The older child will likely try to sit on the baby, dress her in something, or carry her off if you turn your back, so certainly keep the baby's safety in mind, but Big Sister should be allowed to touch and hold and help in any way she can (retrieving diapers and burp cloths, pick up a dropped rattle, dance and sing, hold the baby's hand while she gets a diaper change or nurses, etc.)
Of course, this all might make sense now, while there's no newborn in your house, so save everyone's advice and read it a month after the baby is born when you have had a couple hours of sleep back to back. Until then, do what you need to do to survive, and enlist the help of friends and family (don't be afraid to hand someone a mop if they ask what they can do to help!).