Pretty much ignore the odometer mileage on a used Leaf. Get LeafSpy and see the SOH. Look at Carfax and determine where the car was shipped to, how long it sat on the lot, and where it lived after that. A car that sat at 100% state-of-charge in the sun on a hot dealer lot for months will have a battery that was pre-degraded, and can be expected to have suffered more than a car that was owned, driven, hopefully garaged and likely at an intermediate SOC most of the time.
Unless you are driving at a *constant* speed, you won't get the range shown on the tables. In normal surface-street driving without heat or AC, even though my average speed will be under 30 MPH, I assume I'll get 4.2 miles per KWh for range prediction. I virtually always average a little better. In what passes for winter in Seattle (temps usually in the 40s, almost constant defogger use required, headlights on most of the time), I assume 3.2 miles per KWh because the accessory loads are a killer, and I DON'T beat that prediction as reliably.
I semi-regularly make a 50 mile round-trip that is 80% freeway driving. If I set the cruise control to 52 MPH (which works OK because most people in WA drive slower than other states I've lived in, and they're mostly not TOO deranged by road rage), without any heat or AC I can make that run in barely over 50% depletion of the state-of-charge (by either the dashboard or LeafSpy). If I go 62 on the outbound leg, I can still be unconcerned about my range, even starting from 80% SOC, but I have to drive slower coming home, meaning 55 MPH or less, if I didn't start closer to 90%. If I did that drive in the dark and in the rain (which I don't, since it's to an outdoor recreation site that is not lighted), even starting at 100% SOC I would be nervous, although I would presumably make it as long as I used only the bare minimum of heat needed to keep the windows clear of condensation.
2013 SV no QC, built July 2013
car grew up in San Jose CA, purchased 5/31/17 in Seattle
on 6/16/17: AHr = 56.4; SOH = 86%; Hx = 84.3; ODO = 39,250
bar 12 lost 8/21/17
on 8/23/18: AHr = 54.6; SOH = 83.5%; Hx = 78.2; ODO = 49,746