https://cs61a.org/ has the CS 61A materials.
In terms of number of courses and workload, my experience was that about 5-6 regular (3-4 unit) “courses” in a semester was doable, but any course that has both a lecture/discussion component and any of the following counts as two “courses” for this purpose: lab, large term project (including humanities and social studies courses as well as engineering courses), computer programming assignments (and probably art studio and music performance). Any course on a subject that you find especially difficult could also be higher workload, so you may want to count that as two “courses”.
Also, note that some departments offering R&C courses have pages giving the instructors’ themes and reading lists. You may find R&C courses more enjoyable and easier if you choose those where the reading lists look more interesting to you. For example:
https://english.berkeley.edu/course_semesters/44
https://history.berkeley.edu/courses/undergraduate (not yet updated to fall 2019, since it shows spring 2019)
http://sseas.berkeley.edu/courses (the R5A courses)