Would I be able to pick a server location in Dallas.
Absolutely! As of this moment Dallas is available for 7 Days to Die rentals.
I am also wanting to import a save file for playing as well. Is this doable?
Yes, you can import your old server files via FTP that is provided for all 7 Days to Die servers.
Can the staff of servers help with installing any mods or saves, or is any customization left to the renters of the server?
We'd be happy to install any mods for you. Be sure to open a support ticket with a link to each mod that you'd like installed.