I have a working site using Zen cart (1.53), in 6 languages.
New Site based on 1.54, mobile friendly template.
1. Construct a new site on freelancer's local development server including a mobile friendly template
2. Develop the new site retaining all customer and product details from the old site
3. include all add-ons from the old site including language packs
4. upload and test
5. tidy up file system: locate all obsolete files and images on the server - backup and archive then remove obsolete files
6. organize remaining active images in respective folders.