I have been in the US for a month

I visited to my friend's house in the US and stayed for a month. 
It was the third time to go to the US but this time, I had to change the airplane at Chicago to Nashville in Tennessee made me get nervous. 

I printed out the map of Chicago Cicago airport, made a  duplicate of the e-ticket and some of the information but things went were going well and arrived smoothly. 

When I arrived in Nashville, my friend was were already there to pick me up. It's been for four years since I met him last. 

The first five days, I caught a cold clad and was not in a good condition but after that I recovered from it, we went to Orlando, Florida. It is really nice place and we could enjoyed sightseeing. 

My this trip was completely on my vacation and I had have many good experiences there. 

I tried to conversate have conversations with my friend's family members and his friend but I couldn't express expose well my expression about the things I wanted to. 

I stayed for a month, it was not as short as a vacation but even though I had many memorable expariences there, my memories are fading away a little by little along with going back to normal day. 
I have almost put all of the things back in place from my luggage. I really miss my friend and his grandmother. She treated me like one of the family member. I was comfortable staying at her house. 

I promised her that I definitely will come back to her house in 2014 and she said anytime is okay for me to come back there but she added that there is no guarantee that she will be alive at then because she is 94 years old. 

My friend laughed and said she has been saying for twenty years since when she was in her seventies but she is still spanky so I don't have to worry about it. 

I really want to meet her again and short trip with my friend in 2014. 

do you mean " this trip was part of my vacation" or " this trip completes my vacation"  I am not too sure ??

Sounds like a Great Trip! I am happy for you and hope that you are able to meet his grandmother again :) Ganbatte 

I have been in the US for a month

I visited to my friend's house in the US (when?) and stayed with him for a month.
It was my third time to go in the US but this time, I had to change the airplanes at Chicago to Nashville in Tennessee, which made me get nervous.

I had printed out a map of Chicago airport, a duplicate of my e-ticket and some of the other information but things were going went well and I arrived smoothly.

When I arrived in Nashville, my friend was already waiting to pick me up. It's had been for four years since I last met him.

Within the first five days, I caught a cold and was not good condition but after I soon recovered from it, so we could go to Orlando, Florida. Orlando is a really nice place and we could enjoyed the sightseeing.

My This trip was a completely on my vacation for me, and I had many good experiences there.

I tried to have converseations with my friend's family members, and as well as with his friends, but I couldn't expose well my expression about the things I wanted to say very well.

I stayed for a month. It was not short as a vacation and even though I had many memorable experiences there, my memories are now fading away a little by little along with as I going back to my normal daily routine.

I have almost put all of the things back in place from unpacked my luggage completely. I really miss my friend, and especially his grandmother. She treated me like one of the family member. I felt comfortable staying at her house.

I promised her that I would definitely come back her house to see her in 2014 and she said that any time would be okay for me to come back, there but she added that there would be no guarantee that she'd still be alive at then because she is already 94 years old.

My friend laughed and said that she has been saying that for twenty years since when she was in her seventies, but she is still sparky so I shouldn't have to worry about it.

I really want to meet her again in my short trip with my friend (Your Japanese friend? That's what you've suggested here.) in 2014.

Good work, but there were a lot of things which needed fixing.  In several cases you simply wrote too much, when a single word could fix the problem.