thanks for all the help, folks!
I just went to a couple of stores, and checked out some Ruger Marks of varying styles. Once the salesman showed me how easily the Mark IV's disassembled, I was hooked! Also saw some Buckmarks, but didn't handle any of those. I liked the feel of the 4.75" Mark IV and the Mark IV Lite. I showed her some on-line pictures of various Marks. She chose the 4.75" Standard Mark IV, as well as the Lite (in purple, of course). The range has a 6" Standard that she can try out. We'll go from there. I think we'll buy new. $350 for a Standard or $475 for a Lite...seems pretty reasonable for a solid shooter, BNIB, with warranty.
Thanks again for all the comments and suggestions!
George