I purchased the subject book thinking it would address more of the smaller towns in the country. Unfortunately it only addressed the four in the title. Does anyone know of a Steves book that provides what I'm after? If so, what is it titled? If not, can you refer me to a book by another company that does so and does a good job?
I am a fan of the Michelin Green Guides. They are older but I have found them to be very helpful. Look for their Belgium guide. I have several of them from different countries because I like the way they provide routes of interest and a ranked heirarchy of sites. I have often used them to identify smaller towns of interest during my travels. In Brussels we very much enjoyed the town of Dinant for a relaxing daytrip from Brussels. That was a town that I found in the Green Guide. Its picture and info piqued our curiosity. RIck provides detailed info on his chosen designated sites whereas the Green Guides give a broader view of what is available throughout each country.
I've used Bradt guides for various countries not covered by Rick Steves. I see that they publish several guides for Belgium alone. I found the detail about small towns really good in their guides that I have used for other countries (not Belgium). Consider them:
I would go to your local bookstores and libraries and browse what's available under multiple publishers. I never use a single guidebook for all of our info, wherever it is we're traveling, and supplement those with local tourism guides on the net.
Rick's books are more of a guide to highlights, not comprehensive. I think even he suggests Lonely Planet guides for more in depth information. That's my go-to for places not covered.