Before we went full-time, we had a 25' travel trailer and did the extended weekend and vacation thing. My wife did a combination of most everything mentioned here: she would prepare meals at the house and freeze them to take and would do meal planning to have things to prepare while camping. At the house, we were big crock-pot fans and we had a smaller one in the TT to make all of our favorite recipes while camping. With a smaller frig and limited storage space it took some planning, but we ate well.
Full-timing with a 12 cu. ft. frig and closet-size pantry, we cook and eat pretty much the way we did in the stix 'n brix. (The exception being baking because of the smaller oven. All the baked goods weren't good for our waist lines, anyway!) We have a larger crock-pot and she uses a large electric skillet for a lot of things - even bakes brownies and cookies in it when we don't want to fire up the oven. Laura's a world-class cook and enjoys it, so there's not much motivation for eating out - though we do occasionally. We have both lived in a number of different countries, so enjoy a variety of cuisines, too. We spent this past Thanksgiving through January in New Mexico near my family and I have a photo of Laura making homemade tamales - from scratch - in the rig!
Rob