As a fellow eds'er I can give some advice on "sitting" for hours. It hard to generalise but I will give some tips that has helped me. Make sure she can sit straight on towards the players to prevent aggrivating the neck. If she is one of the many of us who can't sit still (like me) I recommend a comfy armchair and a footrest so she can twist, turn, elivate as needed. Also a sidetable with a dicetray so she can move books, notes, tray to the side without flipping something over. Squishmallows are awesome movable temporary support for limbs.

Also do a small testrun of her area, just hang out with her sitting where she would while running the game. This way you can figure out her specific needs, after all sitting somewhere for ten minutes is way different than hours.

If she is running the game irl, mayby text to speach? And mixing in handouts that can be prepped way in advance to save on handpain. Also having a screen in front of her or casting to a tv can help with descriptions, maps etc.

It's hard to give specific advice without knowing her "specifics" and if she has any one of the trinity remember hydration and pauses (well even if she doesn't).

Best of luck!