Dog games and puzzles
While on most occasions your dog would prefer you to provide the entertainment, when you are away from home that is the time to use things like mind puzzles. Aside from the plethora of mind puzzles, agility equipment and enrichment toys out there, you can do something as simple as putting food in an indestructible dog toy like a Kong that requires them to get it out. You can also freeze these overnight to make them last longer and a great way for the dog to cool down during summer.
Other ideas include setting up items for them to retrieve or placing barriers or obstacles around for them to jump over. You can use rolled up blankets or towels placed on top of each other to create a safe and cheap agility course or you can invest in a more permanent one from the pet store.
Today there are devices which allow you track your dog and wherever it might be from your mobile phone at any time. These are particularly useful if your dog escapes. Dogs like playing games like tug of war, frisbee, anything that the dog can retrieve. Frozen ice blocks flavoured with stock (chicken or meat) or containing chunks of food will entertain your dog for hours and cost very little in summer.