I did SF to LA on one recharge with my Model Y. Wasn't very pleasant (physically painful) and I was following faster cars to get in their wind shadow. It works. I was going as fast as the fastest cars this way. Add hills though and it wouldn't work.

I wouldn't hold out if I were you. 400 miles range will eventually come but what's the point in waiting? EV cars are more pleasant to drive than ICE ones, full stop. Don't hold up, just upgrade to the 400 miles one when it comes out.