I’ve come across some great walkthroughs that guide you step-by-step picture-by-picture on some DS games. At the moment it’s only for a few games including Dragon Quest IV and Professor Layton and The Curious Village. The latter being complete but Dragon Quest isn’t. It’s still worth mentioning that though as it helps you get started on your custom town if you ever get stuck on that.
The site is actually a blog and it can be found on the link below. Hope you find them helpful as I certainly did, especially those Escape puzzles!