I have a golf trip this weekend that is 160 miles round trip on the highway, speedlimit is 75 so I would probably drive 80mph. I will probably drive 20-25 miles while there. I have the 75D so fully charged it would be 245 miles. There isn't anywhere to charge while there or in between. Is there enough range to make this trip?
Looking at Kansas City, there doesn't seem to be a lot of directions that don't have chargers. Take a look at PlugShare.com.
Also, remember, that there are a lot of chargers besides Superchargers. And look for J-1772 chargers along the way and your destination as well. Heck, just hooking up to 120V overnight can add a little.
While charging at destination and J-1772 chargers aren't as fast as Superchargers, they can be quite helpful for providing the "oh crap, I really don't have enough to make it home" charging.
Your biggest saver, by far, will be to drop the speed. Going from 80 to at least 75 can gain a LOT of distance. Just set the TACC on 70 or 75 and sit back and enjoy the ride. Is the extra 5 minutes that you will gain by going from 75 to 80 really worth it? It can also be advantageous to get off of the Interstate and enjoy the remainder of the countryside.
My recommendation for your first trip is to chill, slow it down, look for any type of power at your destination and be a little more cautious for your first trip. Something like driving more than 20-25 miles at your destination is easy to do and you don't want it to spoil your trip.
Play with the power usage as you are driving, watch the power for 10 miles, then change your speed and see what happens.
It is so much easier to take it easy and cautious on your first trip and learn from it, then you will be able to have a much better understanding for future trips.