They won't jump, but they can destroy the roof tile they can reach. So, even roof pieces do require maintenance.

That works. I use a core wood beam as a tight rope. Ground creatures can't cross it. If I need to take a cart or wolves across I just build some floor boards on the core wood beam and then dismantle them after.
https://steamcommunity.com/sharedfiles/filedetails/?id=2973496884
https://steamcommunity.com/sharedfiles/filedetails/?id=2973496906
You should be able to get a cart across your set up.

I like using the roof tiles because they require no maintance.

I like it. Ingenious. Looks kinda like a draw bridge.