I need to do some investigating on this site and the internet in general, but I'm hoping to find a spreadsheet or study somewhere that has a repository of real world Wh/mi use from many MY drivers, which would be better for setting expectations for range.
My generalized, uneducated guess from anecdotal evidence I've seen would be 260-290Wh/mi in the warmer months at 60-70mph, and 280-320Wh/mi in the colder months and/or with faster driving (75-80 mph).
For me, a larger impact on range that I didn't initially expect, was the impact of typically using only 60% of the total available range (charging to 80% and running down to 20%) to reduce battery degradation and extend battery life. For daily driving, it won't be a big deal when I'm charging at home, but on road trips, that would mean that I'm going to need to stop every 2-2.5 hours instead of every 3-3.5 hours were I running the battery from close to 100% down to <10%.