KRISTEN STEWART intends to flee Hollywood for the Idaho mountains – and she’s told her on-off lover Rob Pattinson she’s go­ing with or without him, say insiders.

The 23-year-old “Twilight Saga” star feels both of them need to escape Los Angeles’ hard-partying lifestyle, especially after new photos emerged of Rob looking bleary-eyed at a TinselTown party at which one partygoer can be seen in the background handing a bag of mysterious white powder to another partier, the insiders add.

“Kristen’s beside herself with worry for Rob,” a close pal told The ENQUIRER. “Their recent attempt at a reconciliation has turned into a joke because Rob’s continued seeing other women and partying.

“Kristen has decided enough is enough.”

The two young stars’ romance exploded when she was caught cheating on him with her “Snow White and the Huntsman” director Rupert Sanders in 2012 – and they’ve been struggling to reignite the flame since then. Just days ago, Kristen told Rob, 27, she wanted them to get out of town for good, but he’s still refusing to commit, confided the source.

In the past, they had talked about escap­ing the big city for a quiet, mountain estate.

“They even said they’d love to buy a couple of horses and grow their own organic vegetable garden,” said the source.

Kristen has fallen in love with the mountains in Idaho and is said to be looking around the area of Hailey, where Demi Moore has her ranch.

“You rarely hear about Demi’s activities there because the locals are super discreet,” said the source. “Kristen really likes that and sees this move as a brand-new start.”