Routine drydock repairs etc are often done closer to home port. There are drydocks big enough to handle most ships in places like the Bahamas, Victoria BC and San Fran Cisco and others. If major overhauls like "stretching " the ship are done, those are usually done at European shipyards.
Many of the crew will in fact stick with the ship and become the manual labor for carpet removals, bedding changes, painting , cleaning , varnishing etc.
SOLAS is "Safety of Life at Sea" and are international requirements for things like fire safety, flamability of materials, life saving equipment and such. These upgrades are made to keep older ships, perhaps designed before current SOLAS rules ,compliant with current regulations.
Destiny is not a terribly old ship. She was the first of her class and encompasses many of the things present in newer ships. Her cabins are absolutely HUGE. With some spit and polish she will come out of drydock ready for a couple of years of service. I don't think she has pods and no one is going to retrofit a well functioning older technology ship with pods which are nothing but trouble to most ships that have them.