We are arriving by train at Disney at approx. 10o'clock at night will we be able to get to the Hotel ok at that time of night is it walkable, and do we have to let the Hotel know what time we will be arriving
It isn't walkable, get the No 54 bus at the station, it's free.
Take the bus 54 to your hotel.
Just go to the station where they all are arriving and leaving and then check if a bus is still leaving for Explorers. (mostly they do until 11.25 pm)
Otherwise i would take a taxi (if no bus is available) because they way is quite long, not many footpaths (nearly no) and with luggage...
reception is 24 hours, so that should be no problem.