I was just gonna say. Puppies that old R exactly like kids, short bursts of energy, nap, burst, nap, eat, burst, nap, repeat. 2-3 hours at the dog park is PLENTY. Good physical exercise and definitely could positive for socialisation. What you need to do to get him to tire out is MENTAL exercise. Train his mind. Let him solve puzzles. 10-20 minutes of mental exercise equals 1 hour oh physical! No kidding there. At that age, I trained my boy all the basic commands: sit, stay, down, off, stay down, come. When he was 3 months-5/6 months, our daily routine was like this:
Morning: walk 15-60 mins (gradually increase as he grows)
Learning tricks and mental exercise 5-20mins
Late afternoon: dog park 1-2 hours
He slept through the night regularly.