That's a good question to ask a ME/CFS-knowledgeable physical therapist or occupational therapist who can tailor a reconditioning regimen to your individual requirements, perhaps by telemedicine? PTs and OTs aren't all created equal, but an intuitive one can be a godsend!
That said, I hopped online to see what I could find that might be helpful, and I found this old PR thread. It's from August 1, 2016.
Forums -> Symptoms and Treatments -> Treatment and Therapy -> General Treatment -. How can I rehabilitate my legs after being bedridden?
For me, coming off a year on my couch (thank you, severe FM and PEM) was helped by lots of ROM and relaxed breathing exercises, interspersed with gentle tension-band exercises. Dry needling helped un-spasm my muscles (especially in my neck, shoulders and back), and finding an excellent local non-profit to help (first from my home, and then on site) gave me a new purpose and energized me like nothing else. Don't forget: reconditioning has physical, psychological and
Don't forget to reward your progress with relaxing, genuine smiles for yourself. These calorie-free, un-droppable little rewards further relax your muscles, increase endorphins and stimulate natural breathing.