"Directing a play was the last item on my theatrical bucket list," she said.
"And here we are: little Greytown is on the national theatre grid.
"We're over the moon."
In A Life Sentence, Mr Palmer and Mrs Jesson play married couple Dave and Anne, who struggle to cope with Dave's rapidly progressing Alzheimer's disease.
As per the TheatreFest rules, the actors were allowed no more than 50 minutes on stage -- including 10 minutes to assemble the set, and five to clear the stage at the end.
"They get marked down for going over time, so sets have to be as simple and natural looking as possible."
At the regional finals, adjudicator Deborah Davids had glowing praise for both Greytown actors: Mrs Jesson's performance as the grieving wife "very natural", and Mr Palmer's "stillness as he was trapped in time" and "quick silver mood changes" perfectly portrayed the effects of advancing dementia.
Mrs Penhale-Cashmore, who said she was inspired by a close friend who nursed a partner with dementia, said her actors had worked hard to depict the impact of Alzheimer's realistically and sensitively.
"[The adjudicator] said their performances were delivered with sincerity and respect for their characters.
"That was terrific -- it just what we intended to do."
The Greytown cast and crew, including Mr Palmer's wife Sue as stage manager, will head to Hamilton for the finals at the end of next week, where they will face theatre crews from Dargaville, Hamilton, Wellington, Blenheim, Christchurch and Queenstown.
"The aim is to go all the way," Mrs Penhale-Cashmore said.