WASHINGTON, Dec 13--(AP)--National Park service director and Arno B. Cammerer said today a dozen or so indigent mountain residents of the Shenandoah national Park in Virginia had agreed to leave the park peacefully by April 1.

The residents, who have resisted court eviction and refused to sign for resettlement project homes to other areas, were said to have agreed to leave by that date if the government would permit them to stay until they can "get their roots out of the cellar ."

"Most of those who fought eviction last week," said Cammerer, "have signed the agreement, and the sheriffs whose duty it is to carry out eviction orders have agreed to see that they are out of the Park by that date," Cammerer said.

He explained that more than 300 residents of the Park who had nowhere to go had agreed to leave the area as soon as a resettlement administration homes project is completed, and that about a dozen "ill advised" residents both refused to sign and fought ev iction when it was offered by the State courts acting in suits brought by the State in cooperation with the Federal authorities.

"The sheriffs went to carry out the eviction and reported there was snow on the mountains and there was no where for them to go except out of the mountain roads," Cammerer said. "They said they had their roots in the cellars, meaning their plants for the next season. Now they have agreed to go peacefully if we will let them stay until April 1. Think it was the humane thing to do we have agreed."

Cammerer said the agreements would not delay transfers of the Park from the State to the Federal government.

"We expect formally to accept the Park sometime before December 26," he said.

Plans for the extension were said to have been worked out by the National Park Service, which originally demanded that the Virginia Conservation Commission clear the Park of all families not given special permission to remain after its scheduled transfer from the State to the Federal government Dec. 26.

Sheriff E.L. Lucas, of Page County, who was ordered to remove several families from his jurisdiction, declared that it had been impossible to secure homes outside the Park for some of them.

The Page mountaineers recently came here to say that they would sign any required papers if allowed to remain in their small homes through this winter.