Question: how do you wish your best friend a happy birthday long distance?
Answer: Happiest of birthdays to you, buddy! I hope your day is marvelous, fun, relaxing, and good. ... 
Your side of the world must be booming with bright lights, cool breezes, and loads of booze because it's someone's birthday! Enjoy it to the fullest. ... 
We may be miles apart, but I think about you with every beat of my heart.