I’m a CSU>CC>UC as well.
I currently am finishing up the Spring semester at my CSU, while also taking a class at a CC, and will be doing 6 classes at CC this summer (3 at 2 different ones), and also loading up on about 6 classes in the Fall as well. I am basically in the same situation as you, and am fighting to keep a 4 GPA as well. If you utilize this summer well enough, you could potential have a very comfortable Fall/Spring semester…That’s basically what I decided on doing, as the summer will be a short, quick and painless death.
If you have any questions feel free to message me.