Yep - good plan... but make every button on menu1 auto-activate to go to their relevant 'audio' version. In the sub menus, set every button that goes back to the main menu, or on to another menu, to auto-activate, but make sure that the button to go to the target track in each case requires click. Remember that you are going to have seven sub menus and only one of the buttons on each will go to the footage, the rest go back to a menu.
In operation there will be some pauses - it won't 'feel' fast and slick, but it will give audio clues to your visually impaired users.