So far, what has worked best for me (because I really don't want to make Sulani a destination as it changes the regular world play), was to create a "National Park" with "Peace and quiet" as trait. I built everything I wanted, then had my couple travel there and just call for vacation days every morning (a bit of a nuissance but okay). The only annoying bit was that adding anything to inventory didn't work, but I can live with that.
Also, since my Sims spent Christmas there, you can't put up any of the fence/roof decorations on a community lot, and when you buy other decorations, it doesn't register as fulfilled tradition. They had a great time with just a meal, gifts and holiday spirit anyway :-)
