One interesting paper for the Moderna mRNA platform, from 2017: Distribution of foreign mRNA in test animals, sorted by weight, highest first, after 8 hours:
Injection site muscle, proximal lymph nodes, distal lymph nodes, spleen, liver, plasma, ileum, bone marrow, testes (!), lung, kidney, cecum, heart, rectum, stomach, brain , jejunum.
Interesting that testes is so relatively high up the list, and that more crosses the blood-brain barrier than attacks the jejunum.
http://dx.doi.org/10.1016/j.ymthe.2017.03.035.