Hello Deb,
I live in rural area and have been an avid runner for 33 yrs. Years ago we added a Doberman Pinscher to our family. I take them running on days when the heat and humidity are not factors. I agree that 4 miles is the max they like to run on lead or they start to lag behind. Also, keep in mind that they like to stop and smell the roses

, if you know what I mean. They like to sniff and mark their territory a lot, so that can become somewhat distracting.
When I'm not on timed run, that's ok. I can just stop and do some kickboxing or jumping jacks, etc. to keep my heartrate from dropping.
When we first got Gretchen and Ditka, our female and male; I thought of how much fun it would be to take them to town and run in a popular running area of town. Well in a matter of five minutes I was carrying my sack of dog do do. Needless to say we don't go to town to run very much. LOL. Living in rural area they could find a place in the weeds, off to side of the road for that business. We lost our beloved Gretchen two years ago at twelve years of age.
Also, please keep them on lead as they can become distracted by
squirrels, other dogs, etc and run in the path of oncoming cars.
Good Luck in your decision. Even though it is sometimes inconvenient, I still always have a great time running with my pets.
Dianne