The venue layout is partly determined by the existing layout, partly determined by how much money and work can be invested, and partly determined by what people in the area want. All I can offer on this topic is advice.
First of all, make sure the venue will meet my original list of basic requirements. Seclusion, Accessibility, and Space should all be considered prior to purchasing the venue. Seclusion can be improved with things like window coverings after the purchase, but ideally the building shouldn't be all windows.
The inclusion of Sunshine needs to be considered. Make sure there is a nice flat roof or an area outside that can be made private. A lot of people get hooked on naturism when they feel the sunshine and breeze on their naked bodies for the first time. Many city-dwellers have a difficult time finding a place where they can try this or participate regularly. Although an outdoor space may be difficult to provide, it is a basic feature of all traditional venues. Avoid developing a venue in any building which has no possibility of Sunshine.
A similar indoor space should be provided as well. When the weather turns cold, sunshine through the windows provides a nice alternative. Consider an area of skylights or replacing part of a southern wall with windows. As an example, here is a place in Wisconsin which tries to simulate a day at the beach even in the middle of winter. They even have signs posted about sunburning while indoors.
Successful nudist venues, other types of resorts, casinos, and just about any other place that wants people to stick around, consistently provide customers two basic features: A room to stay in, and food. If these can both be provided in your venue, it'll support a wide range of stays. If these are high in luxury and price, you'll only attract vacationers who are probably older. You'll be competing in a world-wide market too. (I wouldn't go this route.) If the rates are low, it'll support weekend getaways for all ages and support anyone who is traveling on a budget. Others may want it to be a temporary residence while they work in town. Adjust the room rates to be competitive for each market. For food, a variety is always best and make sure it's available whenever people may want a meal. If the hotel rooms have kitchens, or a shared kitchen is available, a mini grocery store would be helpful. If meals cannot be provided, collect menus from local restaurants who would be willing to deliver.
Give people things to do during their stay. Collect recreation equipment, fitness equipment, and anything else that people might enjoy spending time on. If you know anyone who has lots of free time, give them the task of finding good deals on Craigslist for all this stuff. Make sure to keep people busy with games and events as well. Get people involved and they'll develop a strong relationship with the business.
It's also helpful to find a Niche. As an example, there used to be a eBay Store in town which would sell your stuff on the global auction site, but it closed. Perhaps a nudist venue could offer this service as a side-project. Test the waters in different areas and see if anything becomes profitable. What are you, or your core members, good at? A stand-alone business might not stay afloat (like the eBay store), but coupling a few businesses together might. Nudists have skills beyond socializing and sunbathing. Put those skills to good use.
There is quite a lot of variability in how a venue can be laid out and what services it can offer. Don't be afraid to remove things that aren't profitable, and play up things that are. Success depends on how quickly you can find the best balance for the venue.