Hi Rodney,
We are so fortunate to have to here to answer such an important question.
As you point out there is no simple fix and set and leave is inappropriate for full use of the choices of color spaces.
However, Jon, here, are the simple points to prepare you for this well written article, (great for the novice to advanced professional):
There are color spaces for the scene, the capture device, (the monitor: don't use that, it is a WINDOW to you image, not the image) and the pronter. Each color space occupies a different volume in the 3D represnetation of the combinations of 3 componants of color:
HUE (ie how much cyan, magenta and yellow or other color is in that part of the scene.) BRIGHTNESS , SATURATION (How much color is there. Is it a very pale red or intense).
BIT DEPTH: can be 8 BIT or 16 BIT. If you have an image which you process in 8 BIT, you may be losing intermediate colors, (tones and hues) and inadvertantly posterize your image to some extent. Work in 16BIT all the way through.
SIZE OF COLOUR SPACE:Think of volume, not a 2D page. Ther latter gives only one view of the 3D true distribution of contained colors. Use of a wider RGB color space in the capture of an image (camera or scanner) may not be needed, however, for a start, as you get going, that is a good advice.
Use Adobe RGB or Profoto RGB for now as these lose less original data. You may get a better monitor eventually to see them one day and a printer that can deliver these colors in a print.
At present, some printers can deliver colors, especially Epson's blue and green, that cannot be seen on your monitor. However, the Adobe software is very smart and will REMAP the colors to create a perception of a great picture in spite of assigning slightly different colors. Remember, the monitor is merely a viewing port, just like a hole in the fence of a construction site.
Don't switch back and forth between color spaces as EACH TIME to are likely doing some clipping.
As a start, just for now, only convert to sRGB for posting on the web or if you KNOW the image has limited muted colors or you are sending it to a friend who only uses sRGB and cannot fathom an color ideas. You shouldn't use a printer who insists on sRGB.
Costco uses calibrated color managed printers and will take a wide file. You probably will be delighted by their printing!
Although the Epson, Canon and HP printers work within CMYK color paradigms, they are RGB printers in that the input is assumed to be your RGB files. So don't convert to CMYK before printing. Instead, you can get an idea of what it might look at what this might apear in print by using VIEW, then choosing "working CMYK" in the Photoshop top menu bar.
If you have read up to here, now read the PDF article.
Asher