The good news it is very rare for this request not to granted, as about 40%+ of OKW rooms enter on the first floor, EXCEPT Grand Villas, there are only 3 of the Grand Villas accessible with a scooter. If you have a scooter and are reserving a GRand Villa, you must specifically reserve a HA unit when you make the reservation. I've always gotten first floor when needed, as my Mom traveled with a manual wheelchair for about 15 years. Sometimes we'd get an HA room, even though it wasn't necessary, but as long as it was first floor that was our main concern.