J.
Congratulations on your new baby!
I think it's good to try to plan things out, but you won't necessarily find the best solution until the new baby is here. I think your two boys are a little young to be so far away. If it needs to happen, I would use the monitor.
How do you feel about your baby sleeping in your room? The baby could sleep in your room-- for me it's easier to do feedings so you don't have to walk as far, for a few months. If you have a good sleeping baby- I would probably put the baby in the basement with a monitor. The baby won't be able to get up and make trouble like your two little boys can!! If you don't have a good sleeping baby, I think you would have to change plans.
Good luck,
J.