SMP is most definitely a good idea. Try to raise your GPA to 3.0 or above with your prereqs, preferably at CC (although schools like Case Western DON'T accept CC courses FYI). Shoot for above 20 AA and go to the DAT forum part of SDN if you need to ask any DAT related questions.
I know you didn't ask about personal statement, but I'd definitely mention your previous career and non-dental experiences and how it will help you as a future dentist. I had a completely unrelated career for 4-5 years and although many schools didn't care and/or didn't put much emphasis on that, the schools that were interested definitely asked me questions about it during the interview.
If you have any questions regarding nontrad stuff, feel free to PM me