You won't need to drive 60MPH. Model S owners don't do that now, and the 3 won't change that.
A reasonably short break every two or three hours is something you should be doing regardless of your car's range.
I have yet to have the pleasure in mine, but other Model S owners report that long trips are much more enjoyable than in gas cars, because the quiet, smooth ride reduces fatigue, and the breaks are spaced where you'd want them anyway. The only problem right now is that the charging network isn't fully developed. A common complaint goes something like, "I really wish I could take my Model S for this long trip, but there's a gap in such-and-such place, so we have to take an ICE car instead." I don't think I've seen one person say that they made a trip on electricity but wish they had had a gas car instead.