Viola! I got it open.
I soaked the frame for about an hour while I washed the hull and engines reapplying water when I remembered.
Throwing caution to the wind, I took a pressure washer and sprayed it around the frame of the part of the window that opens. While that didn't completely work I think it helped quite a bit. From the inside of the cabin, I used a flat head screw driver and put in front of the handle and ever so gently pried it open while depressing the handle and gently pulling it backward. Thankfully, it popped open on the first attempt. That said, I knew there was significant risk of breaking the window.
After I opened it, I flushed the track, using a water bottle, with copious amounts of water to flush all years of crud out. It took some time but water and an old tooth brush seemed to do the trick. It's drying now and hopefully in the morning I'll have luck on side and it will slide freely. My intent is to try find some marykate liquid roller that hardee, jamestxsd and thataway recommended.
As part of my routine maintenance, I plan to use the 50/50 vinegar solution and marykate as Jamestxsd recommended.
Hope this helps others and gratitude to the wise seamen who ventured forth from the abyss to offer their wisdom. Thank you, Merry Juanderer.