If it was me, I would keep the mortgage and rent it out while I was gone. You could always pay it off at a later date but with that kind of interest rate its better off to have the flexibility. I might consider, refinancing into a 15 yr loan too as you can get owner occupied rates which should be in the low to mid 3’s now or even a 5/1 or 10/1 ARM on a 30 yr to take advantage of lower rates.
BTW, I live in the sister community to yours and have for 12 years. While not a popular belief around here I think LC Oaks is a bit under valued relative to the rest of the market around here. Not that I would expect great returns in the short run but I think LC Oaks will do better than average for this area over the next 10 to 20 years.