The example I saw was an 11 hour journey in an optimal route as described by Google. The Tesla route was a little under 15 hours. It's probably important to keep in mind that the guy had a low battery, so I'm guessing at least 2 out of the 8 or 9 battery charging stops could have been eliminated saving 40 minutes minimum. Probably more like an hour and a half since the route had him going 20 minutes out of the way to the first charger. Make one of those stops a break for a meal (like most anyone would on an 11 hour journey) to fully charge the battery and it starts to make the journey even more like a regular gas powered trip.
If Tesla ever does figure out a model for their battery swapping tech that makes sense, then long journeys in a battery powered vehicle become no big deal at all. Even without it, it's approaching only edge cases that make battery powered travel impractical.