Four feels like Denver, Detroit, DC and Chicago, but I’d want at least one new Canadian team to keep the balance:
In the United States, Denver and Detroit are likely the leaders in any conversation. The league is obviously interested in Chicago, given the fact they are making two Takeover Tour stops there this season, and Washington had a spectacular showing in their stop setting an American attendance mark. Chicago's attendance however, hasn't been up to par with the rest of the tour, although they are selling better for the next Takeover Tour stop.
In Canada, it's hard to point at a mark that wouldn't be a supporter and logical placement for a PWHL team. Edmonton is believed to be the frontrunner based on venue and geography, although attendance in Edmonton this season, whether it was for the Rivalry Series or Takeover Tour, has not been great, and April's Takeover Tour game is selling poorly.