Did Vinnie Ream visit the White House daily for 5 months?

[RJNorton]

"In 1864, President Lincoln agreed to model for her in the morning for five months, and she created a bust of his figure."

The above is from the Wikipedia article on Vinnie Ream.

She wrote about the experience in her diary - some of her words are here.

My question is: did she really do her bust of Lincoln in the White House as she claims? Is there any evidence, other than her own word, that the work was done in the White House?

Adam Badeau reported that Mary Lincoln once said, "Do you know that I never allow the President to see any woman alone?" And we are to believe she allowed a 17-year-old girl to be alone with him daily for 5 months?

I checked several books including Lincoln Day By Day. No mention of Vinnie Ream ever at the White House.

In an 1866 letter to Alphonso Dunn, Mary Lincoln called Vinnie Ream "an unknown person." If Vinnie were really at the White House daily for 5 months how could she be unknown to Mary?

I am curious if anyone has ever come across an independent sighting of Vinnie being in the White House. There are many diaries, letters, books, etc. written by folks who knew Lincoln and were at the White House during his administration - did any of them ever corroborate Vinnie's story?