Hi Donna. I had the same problem, so my other piano is a digital piano that I can plug my headphones into. But it's always hard to get into the music with those huge things on my ears! To your question, the best way to manage files sizes in Photoshop is to plan what your ultimate "plotted" drawing will be. As a rule of thumb, 300 dpi is the MAX that you should set a drawing in Photoshop. Printers and plotters usually don't print anything sharper than 300 dpi. If I'm working on an 11x17 canvas, I'll set my dpi to 200, which would allow me to blow up the image to 24x36 without too much pixelization. If my drawing is on a 24x36 size canvas and will be printed to that size (no plans to enlarge), then I'll keep the DPI at 150.
If you are also doing "layered" TIFFS and PDFs in photoshop, try saving a copy of the file as a "PLOT" file and merge all layers. That should help you reduce the file size and printing shouldn't be too much of an issue in terms of plotting times.
So....try keeping your files under 200 dpi. That should reduce your file size quite a bit. There are lots of other ways to handle the file issue, but try this first and we can go from there. Hope this helps! Let me know how it goes.