What we do manually:
- Know somehow that DC XYZ has a lot of PF usually up
- Logout
- Login
- Select to datacenter travel to XYZ
- Click yes in the following 10 popups that will show up
- Click on your character to join the game, wait for a possible login queue
- Once inside the game, find your desired PF
- Join the PF
- Play the content

What I think could be achieved with the current DC travel + PF (and no, not insta joining another PF in another DC and play the game):
- Party finder could show us all PF across available DCs (the ones we can select when DC travelling)
- If I click to join a PF that belongs to another DC, my slot on that PF is now locked for me
- My client immediately starts the logout+dc travel+login without asking me for any input and confirmation, just put me online on that DC + World please
- Wait for the login queue and to instance in with the PF already joined
- Play the content