Canopy without zipline?

[clcousino]

Hello, I wasn't sure where else to post this general-type question!

My husband and I are going on our first cruise with RCI at the end of March. Our ports of call are Labadee, Jamaica (Ocho), Grand Cayman, and Cozumel. We are in our low 30's, and are not traveling with children. I have always dreamed of seeing the canopy of a rainforest up close, but my DH is fearful of the zipline. Does anyone know if there are any tours where you ride in a 'tramway' type vehicle along the top of the canopy? Maybe an open air carriage with sides? He would feel more comfortable doing something like this.

Thank you!