wp_insert_post get post_title from custom fields

I have a custom post type that don’t need titles, instead the title is like a combination of custom fields (I’m using Advanced Custom Fields plugin for the extra fields):

custom field 1 = This
custom field 2 = That
Converted Title = This And That

I managed to find a way to do that using this code:

add_filter('wp_insert_post_data','gordugo_update_title',99,2);
function gordugo_update_title($data, $postarr) {
global $post;
  if ( !is_admin() )
        return $data;

    if ($data['post_type'] == 'rides') {

        $data['post_name'] = sanitize_title( get_post_meta($post->ID, "pickup_date", true). '-' .get_post_meta($post->ID, "leaving_from", true). '-to-' .get_post_meta($post->ID, "going_to", true) );

        $data['post_title'] = get_post_meta($post->ID, "pickup_date", true). ' - ' .get_post_meta($post->ID, "leaving_from", true). ' to ' .get_post_meta($post->ID, "going_to", true);

        return $data;
    } else {
        return $data;
    }
}

This really works when I’m posting in WP Admin.

Now this is a multi-user site and users should be able to post through front end. I managed to make ACF show in front end through this tutorial: http://www.advancedcustomfields.com/resources/tutorials/using-acf_form-to-create-a-new-post/

But the problem is the post_title in wp_insert_post, it doesn’t get the title from the custom fields.

Here’s the code I’ve been trying to make work:

function my_pre_save_post( $post_id )
{
    // check if this is to be a new post
    if( $post_id != 'new' )
    {
        return $post_id;
    }

    // Create a new post
    $post = array(
        'post_status'  => 'publish' ,
        'post_title'  => 'get_post_meta($post->ID, "pickup_date", true). ' - ' .get_post_meta($post->ID, "leaving_from", true). ' to ' .get_post_meta($post->ID, "going_to", true)',
        'post_type'  => 'rides' ,
    );  

    // insert the post
    $post_id = wp_insert_post( $post ); 

    // return the new ID
    return $post_id;
}

add_filter('acf/pre_save_post' , 'my_pre_save_post' );

this part is not working:
'post_title' => 'get_post_meta($post->ID, "pickup_date", true). ' - ' .get_post_meta($post->ID, "leaving_from", true). ' to ' .get_post_meta($post->ID, "going_to", true)',

Can anyone please help me in making this work. This would be a great help. Thank you.