I hear ya but being in a big old house and the positioning of the router would make things inconvenient, at best, for it to be wired and well placed. With wireless, she'll be able to print wherever she may be working without having to deal with the wires...not her strong suit. She'll also be able to take the printer to whatever room she wishes to work in...or even outside.
The biggest issue for us is that not many printers use transparency paper anymore...rather, they cannot detect it and will just spit it out without printing on it. I've had much success with HP's using it and will probably go back to those. Besides, I think they are the only ones who still make it besides Canon but they will not support its use on their printers. HP is kind of the same but most of their printer will print on it without any issues.
I do have a HP that works and uses it and a 2nd HP all-in-one. So, we do have a working scanner and transparency printer available. Currently, the problem is convenience of use and is why we want a wireless.
Signal strength is great in and around the house even without having a booster. We've had it for almost a week and have printed large image files without any problems. However, she does need transparencies for her home business. So, we'll probably take some transparency papers to the store with us and test them there.