Well, everyone's done a good job answering your questions, but I'll throw in my hat as an additional set of answers for you.
Flashbang said:
What kind of hotels do you guys stay in while on the road?
Hilton, Marriott, Embassy, Westin, etc. Never stay at the cheaper, "lesser" brand hotels - Super 8(?), Ramada's, etc. We've stayed at the Ritz a couple times when the situation warranted. If we fly to an international destination, we'll typically stay at an all-inclusive resort. The boss likes to see us keep it around $100-200 a night if possible. Pilot discounts will usually get you some good prices at most any hotels as well.
Flashbang said:
Does your boss expect you to share a room with the other pilot?
Never, EVER share a room with another pilot. For all reasons previously stated!
Flashbang said:
When you get airlined, is it customary to fly in first or business class seat or do you go in the back? Does it even matter?
We typically go for the cheapest price. Southwest is our priority airline. Typically when we airline its on real short notice so it all really depends. We always fly in the back (Southwest doesn't matter anyways!).
Flashbang said:
Per diem vs. company credit card? Which one do you prefer?
Company credit card. All our Captains are issued a company credit card, and they are responsible for picking up all expenses for the crew while on the road. This includes hotels, rental cars, food, aircraft supplies,tips and fees. If the Captain and I are not together, then I just put it on my credit card, and expense report it when I get back. Entertainment expenses, and alcohol is the only thing the company won't pick up.
Flashbang said:
Do you share a rental car with the other guy or do each of you rent your own?
We always share a rental car. Typically only get one if we'll be at a destination more then a couple days. Any shorter, or if close to the airport / entertainment, we'll typically not bother getting one. We visit a lot of the same cities so we find hotels that have lots to offer close by to them to keep us entertained without having to get a rental car.