Is this hike accessible for elderly and disabled?

Crane Creek doesn't have much elevation, and we will be moving slowly. However the trails are not wheelchair friendly.

What kind of camera do I need?

A DSLR or Mirrorless SLR is great, a bridge camera or higher end point-and-shoot will also do well. If you have a DSLR or Mirrorless, I recommend a superzoom or a wide angle zoom for beginners. A macro is a great thing to have if you want something extra for plant photography.