Hello, & welcome to the world of modern tech!
I also shoot raw, 100%. For initial screening, I use Faststone Image Viewer (it's free):
FastStone Image Viewer, Screen Capture, Photo Resizer ... -- I use Faststone to just browse through the images I download from the camera to cull the obviously-bad ones. Then I use the Pentax Digital Camera Utility (that comes with the camera) to process/tweak the exposure and white balance, exporting the images to a separate folder in high-quality .jpg format. Then I make another pass on the resulting .jpg images with Faststone to crop and resize, exporting to appropriately-sized .jpg images, depending on the intended end use (on-line viewing, printing, further rework). If I will do serious rework on an image, I'll export it as the highest-quality TIFF image and run it through Photoshop where I can work with layers, etc. The Photoshop was a free version of CS2 that was made available online by Adobe a few years ago. However, I rarely need to use Photoshop.
I have experimented with several of the free raw conversion/processing packages (e.g., Raw Therapee, Darktable), and they are good, but I always seem to more-easily get good results from the Pentax DCU.
I hope that helps.
-Joe-