how long does it take? Well, Blue Valley has been in the works for several years, in earnest worked on for about a year. With volunteers doing the work, with a litlle help from the city, things can't move too quickly.
The course I built south of St Louis was about 1.5 years planning, dreaming, finagling with the city, and installing. It's not finished yet, but concrete pads are way down the road. The secret to course design is patience, lots of throwing before something is set down, and sweat. Within reason, the longer it takes to install the course, the better it's likely to be.