Fireshot isn't perfect, but it's darn close. I'm saving a bunch of websites to PDFs and haven't found anything else that works as well or as easily. I had to install a (free) add on program to get it working well for the URLs I needed to save. The extension will tell you if and when you need the add-on and handle almost everything to make it happen.

One teeny-tiny glitch: there's an option to automatically save the result to PDF. The resultant PDF started fine but turned into a "redacted" version about halfway through. So I use a two step process: Step 1: Process and save. Step 2: Convert to PDF.

There's also some glitchiness in susbox's add-on description. There's some html in it that Firefox didn't process properly and left as html. (That won't make sense to most of you, but the net is that you should just ignore parts of the description that look strange.)

I'm a (now retired) professional programmer. This application is really spiffy and I'm impressed.