I'm sure we could come up with other alternatives to the Yangtze cruise if we've known where you've already been, and where/when your exit point from China needs to be. I doubt that your "main alternative" is to leave the country.

If you are against spending the kind of cash a Yangtze western tourist boat takes, then just get to Chongqing and head down to the docks/boat offices to see what's heading out during that week. There might be one of the more decent Chinese boats going out, and should be able to get a 4/3 cruise for RMB 2000 or less. One strategy many people employ on these boats in the off season such as November, is to book a lesser cabin than ask to upgrade once on board. Often the better cabins are going empty, but haggling over the upgrade is the name of the game. There may not be any heat and hot water may only work part of the time and only when the boat is moving. If you don't understand Chinese, try to find some English speaker who can clue you in on the Mandarin announcements. Most of the shore excursions are underwhelming and are reconstructed venues for tourists. If you want to pick one excursion to do (for extra), then Shennong Stream would be it. I would avoid a boat that goes through the locks of the 3 Gorges--usually it's done at night and you won't see anything. You should exit the ship just upriver of that and take the cruise's bus transport to Yichang.

If you need to kill time in/around Chongqing waiting for the sailing, then a daytrip to Dazu Caves is good. Or could head up to Laitan. Or if a few days of waiting, take the bullet train to Chengdu and explore the more extensive possibilities in that area.

I personally would recommend the hydrofoil gambit and speed up the entire Chongqing-Yichang journey to 2+ days with one overnight at Badong by Shennong Stream. But it will take more work/physical exertion and that doesn't sound like what you want to do at this point.