I added another baseboard heat register (my bash of a tutorial by Kris at 1 Inch Minis), this time by the window. Having it on the wall behind the bed would defeat the purpose of adding the detail at all, and the double outlet was already on the inside wall besides.
While I did cut the trim to follow the small outcropping on the left, I didn't bother to cut the trim around the corner post in the back on the right. Cutting pieces that small tends to be more of an exercise in futility with limited results. Besides, a big dresser is going there. Cheating? Smaybe. Less stress? Definitely!
The mismatched seam is definitely less noticeable, too. Hooray!