The Running Diaries by John Trainor

 There is no longer a blog. Now there is only a book series.

Part I: https://www.amazon.com/Running-Diaries-Part-I-ebook/dp/B07DDCFZTM/ref=tmm_kin_swatch_0?_encoding=UTF8&qid=&sr=

Part II: https://www.amazon.com/Running-Diaries-Part-II-ebook/dp/B07HDMHD1P/ref=tmm_kin_swatch_0?_encoding=UTF8&qid=&sr=

Part III: https://www.amazon.com/gp/product/B08XR1BWGC?ref_=dbs_m_mng_rwt_calw_tpbk_2&storeType=ebooks

Part IV: https://www.amazon.com/Running-Diaries-Part-IV/dp/B0CVVFQDGZ