Range numbers listed are accurate for City, and also for highway if you ride in a tuck position. Many choose not to, and that's ok, you just get about 30% more aero drag (30% less range) if you ride upright. So the Zero highway number lists the potential range you can get, which is good to know what you can do if you have to, but many times we choose not to as it is more comfortable to ride in a way that is not the most aerodynamic.
Since the 2018 DSR 14.4 has a 78 mile range at 70 mph in a tuck position you have 4 choices if you want to make it the 70 miles home with some to spare.
1) Ride home on the carriage way in the slow lane behind a big slow truck for at least the first 35 miles hopefully at 60-65 mph, no more. If you're halfway there and you have 60% or more left, you can pass the truck and ride home faster, but it's better to conserve the first half versus being forced to the 2nd half.
2) Ride at 70 mph, but do it in a full race tuck the whole way. It helps to stuff a sweatshirt in the front of your jacket for padding and just lay on your belly with the sweatshirt as a pillow.
3) Pick a place 20 miles from your home you can stop for a warm coffee and some food, or even to do some emails or work calls on your phone for an hour or so parking your bike somewhere with a outdoor plug. You can filter plugshare to show you where the 110 outlets are, but there are outlets in every building that has a light bulb, you just have to learn where to look. With a 2018 DSR you will gain 1% battery every 360 seconds (6 minutes) you are plugged in. So you can stay plugged in until you are sure you can make it.
4) Use google maps to choose a route home but under "options" check the box for "avoid highway". Even if it is 5-10 miles longer, if the speed is 20 miles per hour less, you will be able to go almost twice as far. You will learn how this works over time, but going just 10 mph slower at 70 mph, can boost range 20-25%.
So you have a lot of options. And you can combine all 4 if you want. After you have the bike for a week all of this will seem so easy, sorry if I made it sound complicated. The easiest thing to always do is just when in doubt about if you'll make it, is ride slower the first half to be safe.
Also a pro tip: If the bike at the dealer has been plugged in for a while unplug it. then turn it on and connect your phone to the bike with the Zero app. (have the dealer show you how to pair it by holding the mode button until the Bluetooth logo on the dash flashes) Go to the battery page and look at the volts. If it doesn't say 116, (it probably says 113, 114 or 115 which is ok) then plug it in again and let it fully top off. It's not good to keep a battery full full full all the time, so the bike doesn't continuously keep topping itself off so full it wants to burst, but if you will be riding it shortly, its best to pack up to 5% more range into the bike by topping it off to full full full right before leaving. You'll know when its absolutely full as the green light on the dash will stop flashing and the Zero app will read 116 volts.
You're gonna love your new DSR! If you're anything like me and others, you will enjoy riding it so much, some days you want to ride it 500 miles or more. And you can, you just will need to get fast chargers. But I'll let you learn about that later. But on your 70 mph ride home, imagine riding as fast as you want, and then 10 miles from home you just plug into 2 J plugs for about 8 minutes while you take a pee, and then you can make it the rest of the way. It's a game changer for sure.
Good luck Jeremy and let us know how it goes! And congrats on your new bike!