Either race could involve a clash with the beaten King George favourite, Jair du Cochet, but Thornton is adamant that Kingscliff is ready for his shot at the big time.
"He's all quality when you ride him, and although we can't be sure that he's ready for a Gold Cup this season, I'm sure he has the potential to win us plenty more good races," he added.
Thornton also paid tribute to Alner's other star chaser, Sir Rembrandt, who went down fighting behind Bindaree in Saturday's Welsh National and could also be on course for a trip to Cheltenham.
"Sir Rembrandt might even have won without a blunder early in the straight, but he's a brilliant jumper normally and we now have to keep him and Kingscliff apart and just hope that things go right for them before the Festival," he said.
"Things have been going right for me all season and let's hope it stays that way. I've been around long enough to know it can all go west very quickly, but if 2004 carries on like 2003, then I'll be a very happy man indeed."
