This is the summer when people are discovering the wonders close by, skipping that exotic jet-away for a vacation that's shorter, cheaper and accessible by car. That means a lot of pets are going, too. The trend toward taking dogs along has been building for a long time, with both low-end and luxury hotels increasingly not only accepting dogs but actively welcoming them with such previously unheard-of lures as pet room service and dog walkers. The best way to plan your pet-friendly vacation?