Check out the
OverDrive Link plugin by @jhowell.
It does pretty much anything I could possibly want. Searching for books, or all books by a given author, or keyword searches, then saves the results in a dialog box that lists title/author/series/availability.
You can add a "discovered book" to your calibre library, click the links in Book Details to view the OverDrive catalog page for that book at that library, search for and save the estimated wait time at the libraries it is available at...
I never bother to search the OverDrive websites directly anymore.