Being reliant on an electric wheelchair won't be enough to keep veteran trainer Fred Cowell away from Rosehill.

Plagued by leg ulcers for two years, Cowell is determined to make the trip from the Central Coast to Sydney, where his rank outsider Mighty Lucky takes on an array of rising stars at Rosehill.

The 77-year-old, who started training horses half a century ago, wouldn't miss the best horse he's ever handled contest the Group Three Theo Marks Stakes (1300m) on Saturday.

"Fred's been very ill, but Fred will be there," said his wife and Mighty Lucky's part-owner Irene Cowell.

"Rosehill isn't as hard as Randwick to get around in the wheelchair. He'll be there somewhere, probably round by the horses."

Mighty Lucky is the elder statesman of the Theo Marks and although the eight-year-old is a $61 chance, the robust gelding has long been a favourite of the Cowells.

"This is the best horse we've had, he's been wonderful," Mrs Cowell said.

Regular jockey Chris O'Brien was upbeat as he looked forward to a rare ride in Sydney.

"He's there with a chance. Everything's gone like clockwork this time," O'Brien said.

"The last two preparations he's had hiccups, missed trials, wet weather ... a couple of other little setbacks," he said.

"And fortunately Fred has been able to be involved this time in.

"He came home from hospital just before Mighty came back from the paddock.

"He's been able to get out look at him every day and tell me what he wants done with the horse."