Weather is a concern. Also, be sure to wean your dog to the 2.5 mile run. Don't expect the dog, just like any person, to be ready to run a marathon the first time out. It takes gradual conditioning just like you. Warm up, cool down, etc.
Keep an eye on your dog when you run for signs of fatigue and rest if they appear. They will rest a short while and then be ready to go again. Also, water is a good idea, but don't let them drink too much at a time if you are running, so as to avoid any risk of bloat.
Many people jog and bike with their boxers with no problems at all. Mine run like the wind (with each other in our park) and it is one beautiful sight to see.
Have fun!!