My most successful runs in this game so far have been 'Captain Only'. I find crew difficult to manage and don't usually survive long once all the lvl3 pirate ships are dead.
This strategy relies heavily (at least early on) on the combat AI bug where targetting enemies individually in the pause menu will stop all other enemies attacking you for a few seconds. It's pretty god damned fun though, if you're looking for a change of pace.
Tips for a good captain run: Pick up the Treasure skill early, and island-hop for money for a while, skipping fights and running straight for the chest if necessary. Then go buy a weapon with at least 3 attack off the bat. Now go beat up some lvl2 and 3 pirates until you find a Brown Beard (+3 VIT at level-up) and make sure you have that item equipped on every level-up. Pump INT early on, stop when you're getting +5TP per level and use the item 'Stack of Books' for free TP in future. Then pump VIT forever for the HP boost at level-up. The 'weight lift' item (I forget the name) trains STR for free as well. Gradually pick up all the rest of the skills. For more free TP, activate every Tribal Totem you can find. You can also revisit islands with totems and re-activate them for even more free TP! Finally, you should never need fishing, your time is better spent occupying those training items I mentioned.
For EVEN MORE free TP, go hunt down every Event node you can find. No joke, when you have no crew, every single event is "Captain had a great idea!" pick the +2TP option every time. Profit.
By lvl30 you should be able to visit most of the world map without issue. Pirate battles rely on you grappling over ASAP and then focusing down individual enemies one-by-one. As long as you out-HP them, you're good. I find the Black Cape (+20% dodge) is a good help in this. And of course, consume any White Flags and other permanent stat-boosting items as you find them.
Best weapon to find early on: Spear. Don't forget to pick up a gun, too. Tomahawks are bugged and do no damage, otherwise they'd be awesome. Even a rock is better than nothing.
Sorry if I've repeated anything previously in this topic, I haven't read the whole thing. Hope someone tries this out and enjoys it!