Hi there! Don't know how much I'll be able to help, DD has been cruising for a month or so now, and we've been using a crib sidecar for that time. We were using an arms reach cosleeper before, and she was usually in bed with us anyway, but then she started to crawl and we were
so we subbed it out with her crib.
Our bed is pretty high too and therefore so is her mattress, but we haven't had any problems. She pulls up, and the top bar is about level with her chin. She can't climb out or anything.
About crawling off the bed: she did fall off once.
I think it's kinda a rite of passage, tho. It sounds scary but everyone I know it has happened to at least once. Some things you can do are push the bed up against the wall on the other side; surround the mattress with pillows on the floor so if she falls she lands on something soft; teach her to turn around and back her way off the bed (not kidding! babies this age can be taught this); or nurse her down for naps on the floor and leave her there.
Good luck and HTH.

Our bed is pretty high too and therefore so is her mattress, but we haven't had any problems. She pulls up, and the top bar is about level with her chin. She can't climb out or anything.
About crawling off the bed: she did fall off once.

Good luck and HTH.