Either YA or Children's book, two kids wander with older lady

I read this in the early 1990's, and can remember the plot of the first book very well. It takes place in modern (well modern then) times. Essentially a teen girl was sent to live with this older relative of hers, as well as a boy about the same age (I don't think they were related), and they go on travels. The first book dealt with a cabin of a friend's of the elderly lady, and they start hearing howling at night and the town nearby has people talking about a werewolf, which they then investigate.

It turned out to be the biologist (I think that was what she was) who owned the cabin that they stayed in. She wasn't a werewolf, but she studied the wolves and their behavior and howled with them at night. I believe the series continued in that vein, and I am fairly certain it was one of the Scholastic published series.

I have been trying to find this series again to let my children read it, as I greatly enjoyed the books. Thank you in advance for any help.