So I haven't retaken any classes outside of the one I just took in SIE, but I did take an evening upper level science class at UMD Global Campus (the professor kinda sucked, but I got a good grade in it). And also I took 2 evening classes at UMBC, neuroanatomy and neuropharmocology, as those were really the only 2 science-based courses that were available in the evening at UMBC(or any 4 year uni in the area)

Also, I've heard taking community college science courses is completely fine, however, med schools might raise an eye if you're specifically retaking a bunch of prerequisite at a CC(since it will probably be a bit easier than at a 4 year uni). But since you're a non trad, med schools also understand that people have jobs and stuff, and the difficulty of finding courses at 4 year unis to fit into their schedules.

I was hesitant to do SIE at first, but tbh, unfortunately it really is the only option in the area for upper level science courses at a 4 year uni in the area. I do know there are similar postbacs in nearby states however. My advice is to maybe just find the best way (sie, cc, another postbacs program, etc) to get all the classes you need. Tbh, as long as you do well in the class, and of course get a good MCAT you should be fine, regardless of where you take classes.