When Spok came home he was close to 12 weeks so we were able to get him out a little more.. However, it was in the dead of winter at -20 weather so we did a lot of in house activities. To burn his energy I did mostly mental exercises with him. I tought him all kinds of tricks (targeting my hand with his nose, sit, down, stand, bow, say your prayers, heeling, pivoting on a book to teach rear-end awareness, leave-it, stay, finding a target etc). He learned very quickly so it was rewarding for the both of us and it really burnt that extra energy because he was using his brain.
Check the youtube channel "Kikopup". She has great exercises for attention, tricks, leave-it, all clicker based and using positive reinforcement. These can all be done with your pup!.
Take lots of pictures and have lots of fun!!!