Have you spoken with Oncology? Are they going to want to do radiation therapy for the thymoma? or are they in a wait & see mode regarding that?

Regarding recovery from the surgery itself (mine was 2 years ago):
make good friends with your heart pillow - you will cough and if you do it without support from the pillow it will hurt (and can set back your healing.)

Get something to help you sleep at least partially upright. As bu452000 suggested, a recliner is a nice option... I used a plain foam wedge, some have suggested a similar thing to the wedge I used, but it has arms and is designed to turn your bed into a sort of a chair.

Absolutely pay attention to your weight limits. I forget the exact details, but the doctor or nurse who shows you how to use your spirometer will lay out all the details you need there. No more than 5 lbs for x amount of time... etc. BTW, a car door is more than 5 lbs; so is a mall door.

One I warn people about because it got me during a day-surgery just before my thymectomy.... make sure your anesthesiologist knows you have MG. Having the muscle relaxants they use go into you before they knock you out is very unpleasant.

I didn't have PT to help with the recovery from the thymectomy but I did well after the fact to help with recovery from complications due to the radiation therapy. It was very helpful for me. If your insurance policy will cover for it, ask your primary care physician to write a letter recommending it.