If you are using version 7 & not entirely comfortable with your new Color Palette, best familiarize yourself with how it works here first so you can correctly set your foreground & background paint swatches for this operation.

• rightclick & download this first map
• reduce the colors on the map to 16
• Menu> Colors> Decrease Color Depth
• choose 16 colors
• Optimized Octree
• Nearest Color

We'll use Color Replacer Tool to eliminate extra details in the map by turning those details into the same color as the map background & render a bunch of that map clutter invisible.

• Choose that yellow color in the map as your foreground color swatch &
• activate the COLOR REPLACER Tool
• (Set tolerance at zero on Tool Options palette)
  Pressing your keyboard's Control key turns the COLOR REPLACER TOOL into a temporary COLOR PICKER. (This is one of the handiest features in all of PSP (all versions) & works this same way with nearly all the other tool palette tools.)
  
• Press your Control key & pick the green color of all those tiny streets
• Click that green with your Right mouse button & install it as your background color swatch.
  
  Double-click your normal mouse button to replace all instance of those green streets with yellow throughout the image.
  
• Press your Control key again & go after that next undesirable color in the same manner.
  
  I find a 16 color reduction generally gives me the cleanest image to work with & the most flexibility in my color choices where I don't have to mess around with my tolerance settings or any questionable edge zones, but obviously you can color replace with any number of colors.

Color replacer

If you run into elements that cannot be wiped out globally because you will lose other desirable details:  Choose Paintbrush on the Tool Options Palette and use the Color Replacer to paint over tight areas without affecting other surrounding colors.

Pick that light blue stream across the map as your background color & yellow as the foreground

Paint away that light blue stream with your Color Replacer tool by using the paintbrush. Notice how your painting only affects that light blue stream and doesn't damage W. Edinger Ave.?

That's the power of Color Replacer. Painting with the Color Replacer tool works like a highly selective eraser.  For really stubborn or problem spots like that resistant mapquest logo, keep increasing the tolerance up to the Max.