I’ve written simple rules for generating a hex map, either in advance or on the fly (which works particularly well for solo play). The generator uses a simple system for taking adjacent hexes into account to avoid being totally random. Feel free to let me know if you have any feedback.
You don’t need to. It’s actually quite common for brackwater swamps (mangroves) to exist next to sand dunes.
Really? Hmm. Thanks.
Take a gander at what it may look like: https://duckduckgo.com/?q=mangroves+dunes&ia=images&iax=images