If you work in City A at HQ, and then decide to work remote in City B (and the company approves it), the company is NOT on the hook to pay your travel expenses to City A.

You chose to move, it's your responsibility to cover your travel expenses when you need to be in the office.

Now, if you already live in City B when the company hires you, or the company asked you to relocate to City B, then they should cover your travel expenses when you need to travel to City A.