We (immediate family) live away from all other extended family. My mom is one of 4, my dad is one of 8, and my grandma was one of 11. So growing up, we had to rent out town halls to have our Christmas party. It was a big adjustment going from 200+ people to only our little family of 5 (mom, dad, bro, sis, and self). Just to be honest with you, you probably will feel a little lonely. I am not saying that to be a downer, just saying to be prepared for it. I think it's good that you're planning in advance for fun ways to make it special!
We usually go to Christmas Eve mass in the late afternoon, but we won't this year since we just had a baby a few days ago. Are you religious? This could be a fun way to get dressed up and get out of the house for a while.
DH, LO1, LO2, and myself will be alone on Christmas morning. We will wake up, get out the video camera, start opening gifts, and then cook a big breakfast while A Christmas Story plays in the background. Then, we will start cleaning up and go to my mom's. However, in your case, could you guys get dressed up and go somewhere? The afternoon was always the loneliest time for me growing up away from family. Maybe you could even take a drive and listen to Christmas music and get a coffee. My family always plays board games- could you and dh play a fun game?
Are there any traditions that your family does that you can do at home? My grandpa used to eat peanuts and drink whiskey sours on Christmas. It sounds silly, but it became a tradition and now we drink them every year on Christmas.
For nighttime, you could drink hot cocoa and snuggle in your jammies while reading Christmas books before bed. My little family reads, "The real story of Christmas" and "Twas the night before Christmas" every year on xmas eve.