I just mailed the first complete draft of my favorite out for initial review. The Sonoran Institute and National Ass'n of Counties expect to publish (tentative title) A Field Guide to Community Planning later this year. I have the UWEX volume you refer to and find it reasonably helpful. For resources for the participatory process, however, I would recommend obtaining the U of Minnesota Extension Services Facilitation Resources (in 8 volumes). The best of the academic textbooks is, in my opinion, Frederick Steiner's, The Living Landscape.
Overall, and I say this just having finished 37,000 words of an attempt at it, I do not think any one resource is adequate. Having put most of our books in storage as we rebuild this house, I know which ones I kept out, and which ones I had to go find. Some are technical references, like ITE's Trip Generation, that just can't be duplicated in an overall guide, some are case studies that offer an example in detail that you can't put in one place (Jean Richardson's Partnerships in Communities comes to mind, I think it is essential for planners in rural places, and relevant at the philosophical level for any planner), some focus on one aspect of planning in a depth no overall guide can devote. Daniel' and Bower's Holding Our Ground would be one of those. Perhaps all of us on Cyburbia should assemble an "essential" 100 (or maybe just 50?) book list for planning libraries?