re: Question for those who do both strength training and distance running

With your lifting numbers strength is not a problem! Two things:

1) after you feel comfortable running 3 miles easy, I would switch one run day to sprints and mobility, this will help you so much more in the long term.

2) Keep the sprints and mobility day at least few days from your squat day, you want your legs to feel good before and rest after that day.

Last, what I do, I run a pretty basic 5/3/1 three days a week and run 3 days, with one rest day. I I combine my squat and press days, with limited/sometimes no accessory work. Then I work upper accessory on bench day and lower accessory on DL day. In the end I sacrifice some volume, but find focusing on core lifts heavy (for me) is more important than volume, especially as I age.