A FINAL PROJECT PROGRESS UPDATE:
Well, it's morphed in my brain quite a bit, but here is what I ended up with. And, yes, I have seen the turtles using their tunnels
.
I had just enough of the green vinyl lattice left over [was still shy just a tad and had to use some white], and it was already sized right for my needs. I'll let the pix do the talking. I can lift the lattice off very easily if necessary, yet it's secure enough that it won't get knocked off, and I can still walk around myself without having tunnels in my way, LOL!
Construction phase.......
As seen from 2 different views..... [turtle in pix is a stepping stone -- not real turtle]