Adding a list of shipping addresses to checkout

We have a very long list of addresses we can ship our products to, for customers to pick up. We would like to find a way to add that list (possibly searchable by zip) to the checkout page. We are on a Shopify advanced plan so we do not have access to checkout.liquid. Is there any way to do this?

You could create a custom Shipping rate and call it ‘Pickup from collection point’, then if someone clicks the option you could use their delivery address to send it to their nearest collection point?

Would either be this or finding an app that would enable this for you as you don’t have the ability to customise the checkout.