Switching to MD Only from MD-PhD

After an unsuccessful MD-PhD cycle, I have decided to apply MD only for the upcoming cycle and am looking for any advice I can get:

Stats:
4.0 GPA(c)
518 MCAT
100+ hours shadowing
100+ hours volunteering (local junior high tutoring)
2000+ hours research (one published paper - 3rd author, one paper likely to be published shortly - 1st author)
1000+ hours paid tutoring (also learning assistant for 5 different classes over past 3 years)

I have a full-time nanny position for three young children for the summer which will be part-time during the school year and have also interviewed and been accepted for several scribing positions come fall. Finally, I have signed up at several local hospitals to volunteer, but no results so far.

I applied all MD/PhD last year. I had two interviews at good school, but was rejected at both. I applied as a rising senior (but with AP credits and summer classes while researching, I only had two years of classes prior to applications). I now have graduated (so no problems there) although I am still on the young side (which is what both schools told me when they rejected me -- although they both strongly encouraged me to reapply again this cycle).

I'm looking for any feedback I can get. Thank you!