You might wanna pick up the Open Grave supplement which has encounters in it of various levels. For lower levels they start with two 1st levels, three 3rd levels, and if your group deems powerful enough - one 6th & one 7th. It also includes new monsters to throw at your party as well as some other cool stuff. I personally really love this book, you could design a whole campaign around it if you wish, or simply just pick & choose what you like and slip it in to fit your storyline. I started using a pregenerated adventure and half way through it, decided to combine it with with this book. I chose Vecna as the main mastermind and added in some reoccurring villians from Thunderspire, came up with a few cool ideas to thicken the plot - and created an interesting adventure. If your interested, check out my ideas for the campaign here on EnWorld located at this post link: