CLEP is a great way to test out of courses. Just be sure that those CLEP credits will transfer to a UC, if that’s your final destination. Just do a google search for CLEP along with the name of the university you intend to transfer to. Some of the more selective public universities will not accept any CLEP credits. You can also check the CLEP site on collegeboard.org and see what universities accept which credits. I am not sure how current that info is, which is why I suggest that you check the university site as well.
Basic, remedial classes get you no credit. Be savvy, and find out what’s on the placement test a few weeks ahead of time, and prepare for it.
There is a forum called degreeforum.net - a lot of helpful advice there about CLEP and cost saving ideas in general.
The atmosphere of a cc depends a lot on where it is located, because it largely draws from the local population. Why don’t you visit the CC (or CC’s) you are interested in and get a feel for the environment?
One thing to consider is the fact that transferring in as a junior from a CC to a four year University may be a bit of an adjustment to make. The upper level courses are a transition even for the native students at a university, and will be even more so for a student from a community college. Also, some popular programs at a university may be impacted and may not allow for transfers to get in. It is worthwhile to check this all out prior to starting out at a CC.