Hello fellow Bostonian and welcome to Cruisemates!
I too walk with a cane for distances,and I understand your concerns. We love the stern, and, have not had any issues with our cabin location.
Several years back, we took the Dig Tour,and we had a tour around the pool area, etc, but I don't ever remember having a guide as we walked through the Dig or the aquarium area, just at the outside sea life area. I know we walked at out own speed
There are so many seasickness options out there, and, these ships have great stabilizers, most people are fine...ginger also works according to those who have used it.
If need more info, just yell