You can convert this JSON to CSV in a single line with jq.

jq '.data.headers | [.sender, .to, .subject, ."x-received-time", 
.received, .from, .date, .id, .to, .subject, .fromfull] 
+ [(.time | tostring)] | join(", ")'

Breakdown:

• .data.headers - Emit headers as an object
  • If data contained an array of headers it would be .data[].headers
• […string keys list…] - Emit string values as an array
• + [(.time | tostring)] - Emit time as a string and add to the array
• join(", ") - Join the array values using a comma and a space
  • Substitute your favorite delimiter here

Since you are working with JSON files, why not parse it as such? Install nodejs-legacy and create a NodeJS script such as:

#!/usr/bin/env node
// parseline.js process lines one by one
'use strict';
var readline = require('readline');
var rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false
});

rl.on('line', function(line){
    var obj = JSON.parse(line);
    // add the fields which you want to extract here:
    var fields = [
        obj.data.headers.to,
        obj.data.headers.subject,
        // etc.
    ];
    // print the fields, joined by a comma (CSV, duh.)
    // No escaping is done, so if the subject contains ',',
    // then you need additional post-processing.
    console.log(fields.join(','));
});

Assuming you have a valid JSON string on each line of a file:

node parseline.js < some.txt

Or if you really want to read a single file and parse fields from that:

#!/usr/bin/env node
// parsefile.js - fully read file and parse some data out of it
'use strict';
var filename = process.argv[1]; // first argument
var fs = require('fs');
var text = fs.readFileSync(filename).toString();
var obj = JSON.parse(text);
// add the fields which you want to extract here:
var fields = [
    obj.data.headers.to,
    obj.data.headers.subject,
    // etc.
];
// print the fields, joined by a comma (CSV, duh.)
// No escaping is done, so if the subject contains ',',
// then you need additional post-processing.
console.log(fields.join(','));

Then run it with:

node parsefile.js yourfile.json > yourfile.csv

You can use jsonv from GitHub

And then the following command:

cat YOUR_JSON_FILEname | jsonv to,fromfull,id,subject,date > output.csv

Here's a gawk script I just whipped up for you!

#!/usr/bin/gawk -f
BEGIN {
  FS="\""
  output=""
  nodata=1
}

/^"data"/{
  if( ! nodata )
  {
    gsub("|$","",output)
    print output
    nodata=0
  }
  output=""
}

/^"[^d][^a][^t][^a]/{
  if ( $2 == "to" || $2 == "fromfull" || $2 == "id" || $2 == "subject" || $2 == "date" )
    output=output$4"|"
}

END{
  gsub("|$","",output)
  print output
}

It should work on a file with a bunch of like entries. If you want to add other items to the list, just add them in the if statement. I did find one problem with your data set though: the dates. They contain commas so it can't be a true CSV. Instead I just separated it with another character.

Here is an awk implementation:

   awk -F ":" '{gsub("\"","",$1);key=$1;sub(key " ","");gsub("\\","",$0);value[key]=$0; if ("fromfull"== key) print value["from"] ";" value["to"] ";" value["fromfull"] ";" value["id"] ";" value["subject"] ";" value["date"] ;}' jsonFile > csvFile

This script read line until found "fromfull" line, than print csv line, so it should works also with multiple sequences.

This is the result:

  ""Help with this project" <>";"";"";"1414427328-2345855-frank";"Help with this project";"Mon, 27 Oct 2014 09 03 14 -0500"