It seemed like you wanted something fairly simple and colorful. I thought that using text over a background may work best to meet the 'simple' part, and add the colors you recommend in the brief. I thought this font, with it's rounded edges, would be friendly-looking, and a bit playful with the R. Because most of the lettes had a space at about the same height, I thought that extending that over all the letters and the background would make an interesting visual effect, and making the upper and lower parts of the letter different colors would add further interest.
Let me know what you think, please, particular in regards to the colors. If you want different shades for the colors, I would be happy to make those changes.