Ruin Explorer
Legend
I just want to second (third?) this incredibly hard.Keep on the Shadowfell is a grindy dungeon crawl that absolutely does not play to the strengths of 4E. It runs almost exactly counter to them.
Keep on the Shadowfell nearly put my players off 4E, despite being enthused about it, and I had to gradually win their trust back. The follow-up adventures are also awful. They were so bad that I went back to writing my own adventures, something I hadn't done for D&D for a long time at that point (because writing adventures for 3E was such a chore).
Luckily it's a lot easier to write adventures for 4E than 3E or even 5E.
The other major thing I'd say would be remember to use the page 42 table in the DMG and use it generously.