Conversation With a Ghost

I'm bored to death and haunted by the puzzle of the Conversation With a Ghost song for some reason so heres what I'm thinking:

Conversation (This song isn't two sided. So why is it titled conversation?) With a Ghost (I get the feeling this song is someone rereading a letter from a soldier whom they loved, old lover, or their father who has died while away)

I'll respond to you in letters.
Sorry so slow, sorry so few. (Slow because he's far away, few because he's busy)
So far I'm much better. (Maybe he was sick in his last letter.)
The complaints here have been few. (But this kind of makes me think it isn't a soldier. Also, would the complaints be coming from other people?)

How have you been?
Have you been to the races? (Horse races? Car Races? Track and field races?)
Did you take my mother? (If it is a father- taking your grandmother makes sense maybe, if it is an old lover- why are you still that close to his mother?)
Is your sister in braces? (Braces on teeth? I also get an antique feeling from this song that makes me think maybe these could be braces for polio? This is the father asking about younger sister to show he cares or the lover making small talk)
I wish I could have been there to see you through. (Is this about the braces? Could a sister in braces have been that bad? I feel like this is a masked statement about something else though. An abortion if it is a lover? Childhood/hard life if it is a father?)
Hey, are all those things you told me still true? (This makes me feel like its a soldier looking for something to hang onto for when he comes back, but it could still be a dad seeing if he's still loved.)

Do you remember that time It was cold in the park?
You were running a race. (The same kind of race as "the races?")
I was there on a lark.
Who would've thought that New York could be such a small town? (Just reminising on a time they reconnected. I'll take this verse at face value.)

Margaret is tired.
Let's let her get some sleep.
Bored with these letters.
Let her count her sheep. (Who is Margaret? The reader or someone near him while he's writing the letter telling him to turn off the light?)
So goodbye love, goodbye love.

I need to get a life right?