Have you been to Yellowstone? What do you already know? Are you actually working in the park or nearby.
There is very little phone coverage and almost no internet coverage available for the public. You can buy minutes on the Internet at some of the hotels (such as Old Faithful Inn). Verizon is by far the best choice (ATT hardly exists) and it is very spotty. Verizon just last year extended 4g into Old Faithful area. I believe the other areas are very hard to get connection. I am most familiar with Old Faithful area as that is where I work. Yellowstone is huge! Depending on where you are reasonable shopping can be 20 minutes or 2 hours away. Good shopping is in Boseman. Will be very crowded next year with many traffic jams (both man made and nature made - think bison jam.) crowds will be particularly bad from middle of June to end of August. Weather will range from below freezing and snow in May-June and last part of September to 80s in the middle of the summer. But it can snow any day of the year. Think Christmas in August- a Yellowstone tradition.
It is a magical place to live in and a little daunting to work in.
I'm sure I've missed a lot. Any other questions. BTW you'll love it.