Here's my workflow using Geequi, Raw Therapee and Gimp.
I chose the picture in Geequi and exported it to Raw Therapee. Here is the original shot:
I changed the pp3 to Deep Shadows, which is one that is included with Raw Therapee. I enabled film simulation and chose Fuji Velvia Generic 100 at 16. I changed white balance to 5178, exposure compensation to .83, exposure saturation to 22. From here I exported as .jpg and opened in Gimp. I cropped to my liking, made a small level adjustment, very light unsharp mask and was finished. Granted, there's a lot of noise, but considering the image was made with a K100D and a Quantaray macro zoom, I'm ok with it.
I am posting this not to show how a post-processing master might use Raw Therapee to make the perfect image, but to show anybody sitting on the fence on raw processing how easy it is. For the most part, the adjustments were made by trial and error. I used the section in RawPedia, "Basics", as my guide.