Some people might disagree with me, but I've NEVER used any kind of soap when washing my DO's, even when they're brand new. You might want to rinse it, and even though it is pre-seasoned, I'd still wipe it down with a light coat of oil. DO NOT use any metal utensils while cooking with your DO. The metal can scratch the cast iron which will allow rust and removes the seasoning. My preference is to always use wooden utensils. And once you've finished cooking with it, simply wipe it out and season with a light coat of oil. If some of the food is baked on, you can boil a little water in it and scrub with a stiff nylon or cast iron approved brush.
As far as the lid goes, I always oil the the lid inside and out and the outside of the DO everytime. Some people don't, but I think it helps maintain the metal. Otherwise, nothing special is required for the lid.
I honestly haven't heard anything about high acidic foods being a problem for a DO. I've never worried about it and have never experienced any problems.
Camp Chef is good DO. My 10" is a Camp Chef, and I'm planning on buying Camp Chef's 12" deep soon.
I think you're girl friend is smarter than you think. She's giving you the DO as a thank you, but I bet she also realizes that she's going to get a whole lot of good meals out of it!
Have fun with the DO.. Let us know how your meal turns out. I hope this was helpful.