Just back from kedarnath prepare yourself to tackle cold and chill weather, unexpected rains, sudden change in weather. no matter how much you plan and prepare be flexible with your plans. it's not crowded but prebook your accommodation if you plan to stay there.
Plz carry some warm clothes with u. also plan how would u like to complete 15 km treeking with horse, chopper or by foot. don't be worried abt a accomodation as it will the last week of season so u will get it on cheaper rates.