Xbee for Arduino recommendation?

I am a teacher and my students and I participate in a solar boat competition each year to race for speed and endurance. I am convinced that the difference between 1st place and 2nd place is a software solution, but for that, I need live feedback and battery voltage and how much current it is used. I thought to myself, of course, the Xbees are going to be my best bet, but there are so many options that I do not know which is the best solution for me. At the furthest point, the boat will be roughly 1 mile away from us but would hate to invest in a Xbee that only reaches 1 mile and keep losing connection. What do you guys recommend? I have a few hundred to spend on Xbees and any accessories (antennas), I need this to work with an Arduino microcontroller.

I would suggest using the XBee PRO SX. It will give you the longest range for the buck.