My boys are 20 months and 1 week apart. I stayed home for 6 weeks before going back to work with each, but my husband is home days and works evenings. We have never sent our children away just to have alone time with the other, unless it is a "date" with mommy or daddy. (We do have someone who comes to our home when our schedules overlap, but that is hardly a preschool program).
So no, we do not have any help. We separately share the child-rearing responsibilities except for Saturdays, which are our "everyone's home" day.
At first I was able to get my kids on close to the same napping, meaning that when my toddler napped I could usually get the baby to sleep, too. Babies nap a lot, so for me just nursing in bed while my toddler napped and then napping for a bit with the baby was a lifesaver. Meals were easy--baby latched on, toddler at the table. Or, baby napping, toddler at the table. Or, baby in bouncer, on floor, etc. with toddler at the table.
The pack-n-play was my friend. It gave my infant a safe place to rest or just "hang out" so my toddler could still roam free.
Now that my boys are 2 and almost 4 years old, they adore each other, play together, pummel each other, torment each other, push each other, sing to each other, sing with each other, read to each other, and talk about their baby brother (not due until March).
Challenges were for us when they stopped consistently napping on the same schedule. That was really only hard for me because I often need a nap myself. I average about 5 hours of sleep most nights, so by the end of the day I am desperate for a short nap before my other day (when my husband is working) begins.
Toddlers do not understand safety, so you cannot ever leave your infant alone with an awake toddler (even when the toddler appears to be playing contentedly with his cars on the couch and the baby is happy in the exersaucer and you can see NOTHING that could pose a danger to either child and you know you will only be out of sight for a matter of minutes...).
I guess we would never have thought of NOT having both of our kids at home. I would probably have wondered where else they would be. Now that they share a room and are able to play and talk well I can't imagine them farther apart in age or how sad they would be without each other.
Good luck--there will be bumpy, crazy, weepy moments, but in the long run it can be so wonderful have them close in age. Try for the one-on-one mommy/daddy dates with each, though. Our boys love it!