When going on retreat, it is advisable to speak to the teacher and place where it will be held to make sure there is access for you if you are a wheelchair user or have an issue with stairs. When I was well enough to go on retreat, I found my local retreat centre to be incredibly accommodating and would give me a ground floor room to avoid the use of stairs. If you need to be close to a bathroom, that can also often be accommodated.
In my experience, retreat centres often have guests with all manner of chronic illness and disability and most of your requests will be ones that they are used to dealing with. If not, it is good to give them a challenge and you will likely make life easier for someone going there after you.
Fortunate Way Zen 福 道 