Keeping wordpress dashboard and content after connecting domain to squarespace

Working on a site for a client and there are 3 components I'm dealing with; domain hosting (a small orange), current site/hosting (wordpress.org) and new the website (squarespace). Once I connect the domain to squarespace, is there a way that access to the wordpress dashboard still be available. Because Im assuming that mywebsite.org/wp-admin will not function because the domain is not pointing to wordpress anymore. I know that the content doesn't disappear (I still need access to flip on new site).

Does the fact that its .org not .com matter? Is it a matter of properly mapping the url? 

After switching to squarespace, my client still needs access to the wp dashboard because of the content, tags, library, and post they have built. Please advise.

Hi,
There are some ways to solve this problem!

1. You can connect new domain to your WP website.

2. Add parked domain that served on that server by other persons.

3. Connect via IP/~username if you are on cPanel.

4. Get the database on files and clone it to the localhost version.

Please contact me via DM for the custom work, if you can't do via these guides.

Please use the like button if it helps you!

Best,
Leopold