I do 3x strength and 4x running. Everyday is a combo day except my last running day of course which is a long run day. Other 3 days are rest days or variety days as I call them. Variety days can be easy bike rides, swimming, walks, hikes, sports, whatever. Just anything to get me out.
To answer your question about strength I focus mainly on the big 3. One per day with 2 accessory workouts. Always lift first even if you are prioritizing running like me.