How long will my ganglion cyst surgery be? And how long do I have to stay in the hospital afterwards?

Easy questin. The producer will take about 15-20 minutes, and you will the hospital in about hour after that. That the normal course.
Depends. It will depend on the experience of your surgeon. Most hand surgeons perform ganglion excision as an outpatient in less than 20 minutes. You would go home about 1 hour later.