To get an island-heavy world, increase water coverage, and optionally reduce its scale. Play around with map preview to see how it ends up!

Core Inclusions

Dredgeworks: The focal mod of the pack. Ore patches now generate into and under the water, special hardware is available to extract and relocate these ores, and refined concrete serves as a new landfill alternative with higher flexibility but increased complexity.
AAI Containers and Warehouses: High-capacity storage. Included for its usefulness when buffering materials in isolated sites such as aquatic extraction platforms.
AAI Vehicles: Ironclad: Seafaring vehicle useful for pre-jetpack transport, and establishing a beachhead against biters (particularly if playing on an island-heavy world).
Cargo Ships: The sea counterpart to trains, providing crucial long-distance water logistics. Dredgepack activates the option to allow oil rigs without chemical science, to facilitate early extraction if your closest oil isn't on land (or near enough to build refined concrete out to).
Jetpack: Provides personal mobility over all terrain, including water. Makes offshore construction much more practical.

Extra Add-Ins (and why you might want them)

AAI Industry: Adjusts and extends a wide array of early to mid game manufacture processes, extends the burner phase and alters the distribution of resource consumption. Not for everyone, but has an interesting tool in its Fuel Processor, which allows the creation of a condensed processed fuel that is convenient for operating jetpacks and seafaring vessels.
AAI Programmable Vehicles: Not currently available in 2.0. Allows remote command of your vehicles. Pairs well with the Ironclad for en-masse coastal biter removal.
AAI Signal Transmission: Infinite-range interconnection of signals across any number of electrical grids. Can come in useful for highly distant outposts that aren't connected directly by a power line.
Alien Biomes: Primarily beneficial for the shallow water coverage, making it easier to get in and out of water vehicles and possible to have an "intersection" between land and sea transit. Also pretty.
Combat Mechanics Overhaul: Makes walls substantially more effective against spitters, in turn making "beachhead" bases much more practical to establish.
Handcrafted: Adds toolboxes and consumable hand tools which accelerate manual crafting. If you're disorganized or just like cobbling things together by hand, this comes in fairly useful.
Squeak Through 2: Allows you to snugly fit in between just about any structures in the game. Very convenient for dense facilities and offshore operations.