I read the other responses, but this is what I would do... I would change out the blue color, maybe a limish green or a blue than is more similar to the blue in the bottom butterfly wings on the quilts or the background in one of your pictures. Obviously, not that bright, but more in that color tone. Painting the trim would make it more girlish, but I think you could make some other changes before making that decision. If you have it in your budget to buy fabric, I would cover your beds in a solid color fabric to make the quilts pop more. Try hobby lobby for some cute wall decor. Last year, I found an adorable glittery wood wall letters that said "kisses" in the valentines section. It goes perfectly in my 5 year olds room. I would hang something like that above each of their beds. The dresser needs something cute on it. A little grouping of bears, blocks, picture frames or just something more decorative. You could paint some butterflies on one wall with just a few small pints of sample paint. You can get these at Sherwin Williams for $5 each in their cans designed to help you decide on a color and you can mix them in any of their colors. It would add a lot of pizzazz to the room, and a butterfly shape is pretty simple shapes put together. I would then add some cute basic curtains, maybe in a solid color. Good Luck, I'm sure they already love it, we always overanalyze these rooms, and I am sure they love it just the same now as they would later.

I'm currently working with some blues... and have ended up with Pratt and Lambert colours off their OLD fandeck. Specifically, Loch Lomond and Blue Pride. They are two different LRV levels. Both very subtle colours with gentle violet overtones that don't seem to have any close matches in other brands, and trust me, I've looked. KarinL

Either a simple wooden or padded headboard or a book shelf headboard to encourage 'reading' in bed is a good idea. You can have fun with color either way. Build some model airplanes to suspend from the ceiling. You are bringing back memories...my 25 year old's nursery and toddler room was done in airplane. Fun memories!

On the other hand, you could take a green from the woodland mural and paint that under the mountains (see the green throw in your photo)and on one between wall, then take a tan color from the mountains and put that under the woodland and on the last wall. Lots of play and imagination to be generated by that. Your furniture would stand out against darker shades.