That's looking really good! I'm glad you're finding CGALIB useful! In my latest update I forgot to expose the screen attributes too, but it's relatively simple to do. I'll probably get around to that once another update is necessary.
The new bitmap editor is still a bit limited (24x24 tiles, and only 24) because it's really only there to get people started. Your own is probably better for your purposes. For my own projects I'll probably continue using The GIMP to make screen-sized collages of bitmaps and writing a bespoke asset maker for each game to grab the bitmaps.
I'm looking forward to seeing where your RPG project goes.