Using composer.json vs files in modules dir

[psy]

I'm developing a module to integrate BigCommerce's Stores API (https://developer.bigcommerce.com/api) with PW. After a steep learning curve, I managed to use composer.json to download the latest version of the API into a 'vendor' directory.

{
  "name": "processwire/processwire",
  "type": "library",
  "description": "ProcessWire CMS/CMF",
  "keywords": [ "cms","cmf", "content management system" ],
  "homepage": "https://processwire.com",
  "authors": [
    {
      "name": "Ryan Cramer",
      "email": "ryan@processwire.com",
      "homepage": "https://processwire.com",
      "role": "Developer"
    }
  ],
  "require": {
    "php": ">=5.3.8",
    "ext-gd": "*",
    "bigcommerce/api": "*"
  },
  "autoload": {
    "files": [ "wire/core/ProcessWire.php" ]
  },
  "minimum-stability": "dev"
}

Using composer.json and its autoload.php feature works great. All I need in my template is:

<?php

use Bigcommerce\Api\Client as Bigcommerce;

Bigcommerce::configure(array(
    'store_url' => 'https://www.mybigcommerceshop.com',
    'username'  => 'admin@mybigcommerceshop.com',
    'api_key'   => '8fab84ce1776dbba18665xxxxxxxxxxxxf'
));

$ping = Bigcommerce::getTime();

if ($ping) echo $ping->format('H:i:s');

My dilemma is that the files are in './vendor', not './site/modules'.

Not everyone will use composer.json so looking for recommendations on how to best code the module to first look in './vendor', then if nothing there, look into './site/modules/BigCommerceApi/Api' to load the files (which may be out of date) and instantiate the API.

Suggestions?

Using: PW v3.0.24

[LostKobrakai]

Read this one: https://processwire.com/blog/posts/composer-google-calendars-and-processwire/