Basecamp is clunky, and hard to print to a specified scale. You can choose your grid units in the options (LatLon, UTM, etc). These get printed on the borders.
Zoom in and out to fit everything onto the page(s) you want. It will print a scale, but you can't specify what scale. It just puts a scale bar on the page. Use Print Preview to check.
I use OziExplorer. Also a clunky interface, but a lot more control over scales and page sizing. Also around $130 for a one-time purchase licence.
I first bought it around 2003(?), and upgraded free of charge ever since.
I suspect there may be better software around these days. Maybe not.
Finding maps can be hard, too. For WA maps, checkout The Explorer's 25k and 50k SW series, among others. See
Mapworld