Aslan is missing :(

I am heartbroken and miss my puppy. We decided to take Aslan and Lily with us to Kevin's grandparents house for the 4th of July. He needs to socialize so we thought it would be the perfect opportunity to have him meet a lot of people. We gave him a bath (what an experience that was!) and got him brushed all shiny and nice and off we went. He was great all day, he stayed right with us and whenever we went inside we put him in the little penned off area to keep him safe. Well when I was inside nursing Kobe and putting him to bed, Kevin decided to let the dogs out of the pen right when the fireworks were going off...then left with Katie to go down the street to see some other fireworks. Apparently the loud noises scared Aslan and with nobody he knew around, he bolted. When Kevin got back with Katie and couldn't find him, he came inside and told me and we all went looking for him. We looked on foot and in the car for hours, I called him until my voice was hoarse. At midnight we were exhausted and didn't want to drive back to Denver without him so we got a motel for the night. We got up really early and searched again, we went to the Humane Society..twice. We made 100 fliers with his picture on them and put them up everywhere. Last night when we were about to leave to go back home, Kevin's aunt called and said she saw him walking in the road in her neighborhood (a couple miles away from his grandparent's house.) We raced over there but she had lost him in the bushes by the time we got there. We stayed till 1:00am driving around, calling and looking for him....but he was nowhere to be found. I am just so sad and worried about him. I know he must be terrified, alone and hungry, not knowing where we are or where he is..... he is only 5 months old. Of course this has to happen right before we are supposed to go on a week long trip to Montana for Kevin's family reunion. We were going to take him with us because we didn't even want to leave him in a pet hotel and now instead we have to leave him roaming on the streets alone not knowing if we will ever see him again. :(