It can't hurt to call up some rental houses that deal in film gear and ask if you can come in and familiarise yourself with the equipment.
All the rental houses I've worked for have always been happy to let assistants do that, especially if you've already read all the handbooks. After all, it's in their interests that the people using their gear are familiar with it.
I absolutely agree with Dom. Plus, if you spend some time there, you get to meet assistants, operators, cinematographers. I know many many people who have expanded their connections network just by working/interning even for a short time at a rental house.
As for the Maine Workshops, I'm quite biased: I took the Camera Assistant workshop (taught by Doug Hart) and the Camera Operator workshop (with Rexford Metz), and I just cannot recommend them both highly enough: fantastic experience, great instructors, beautiful location, and most importantly, you definitely learn A LOT, no matter how much previous experience you have.