We've lived in a two-story house for 16 years. We didn't put the kids upstairs until they could get up and down stairs safely. Safety gates aren't enough . . the little buggers find a way to climb over and then fall even farther down the stairs.
We are those dreaded co-sleeper families though
. . .our 2 1/2 year old still sleeps with us. But one of the things we did with our daughter was put her crib in the office down the hall and make that her bedroom for awhile. We've also had our toddler's crib in our room.
I'm like you . . .I never felt safe with the kids upstairs until I knew they could negotiate stairs. Fortunately my husband is a true believer in co-sleeping.
Is there a room downstairs you can temporarily turn into a bedroom?
The kids ended up loving having the upstairs . . . .and taking pillow rides down the stairs. My husband taught them that . . this was his grandparent's home and he did the same thing as a kid and so did his mom. My daughter had her grandma's room up until we made it over into our son's room. Kinda cool to grow up in the same house your grandma did.
Congratulations on the new house!