Don - I hope this is a real-life example and not a hypothetical. If so, I urge you not to think in terms of trade-offs - one, because it's a negative way to think about a project (even if it seems practical); two, because you and your team are more than able to turn these negatives into positives; and three, because in your heart of hearts you know that none of these so-called trade-offs/negatives are in reality any such thing, save nos. 6 and 7. (Imagine you have a potential client, a wonderful and kindly man who asks you to build the best course you can for his community, but for even less than a modest budget. I bet if you took the job you'd find a way to pull it off; so treat yourself with the same respect, and the same discipline, as you would this poor but benevolent client.) So:
1) Go even further than you did at WP in creatively conceiving of and designing a minimal and sustainable irrigation system, and be proud of it and of its results.
2) Keep thinking about and routing and designing different versions of your golf course until you have come up with a great design that is actually made better than you ever imagined for having to factor in/integrate a) minimal irrigation, b) longer, drier grass that flows with nature's whims, c) less bunkers, d) generally smaller greens and less turf, combined with e) broad double fairways and the occasional double green.
3) Figure out something better and more attractive than a double wide. Ask for help and think imaginatively: maybe a local builder of pre-fab homes/cottages can donate his labour in turn for a special membership.
Dont wait. Don't postpone the 3 hole course for children. With it on opening day, you will have set a tone for life, and garnered a great deal of good will; with only a promise of such a course, you are (i.e. you might appear to be) just another slick operator who promises a lot and delivers little.
Peter