your first weapon to keep is the AK47
it is not special or effective but the enemies on rook island dont have a lot of armor anyway
its also important to keep an all-round weapon in your inventory because if you dont have a weapon that is focused on hunting/combat you might die in moments that could awake anger

your second weapon should be either a winchester shotgun (using the real name here)
unlike the shotgun's in any other first person shooter this one runs out of ammo as soon as you pull it but its a strong backup weapon to use for hunting or fast disposal of one or two enemies

if you dont have enough funds to afford that weapon then take the second smg
your second weapon slot should be kept free for pvp weapons and smg is master of disposal of weaker enemies but is less effective in hunting

in this slot you might want to keep a weapon that excels in mass kills like an hmg my favorite is the second hmg keeping a weapon like this in your inventory could be the key to liberizing rook island as it is usefull in offensive AND defensive functions the hmg can best be used for taking out large groups of pirates but is also usefull to take down strong enemies like bears

in this loudout slot you should keep a weapon that fully excels in one stat but leaves the other stats behind him or just a special weapon or item you just cant miss
i personnaly keep a flare gun here i find it usefull for pirates and hunting (but im a little savage i suck at stealth the only gun i use for stealthy positions is a supressed smg)
but i can recommend to keep any of the remaining weapon types here like the rpg7 flamethrower or even a sniper rifle but for a fully all-round loadout you should keep either the grenade launcher or a sniper rifle here
your sniper rifle for positions that require or prefer stealth

your grenade launcher to unleash hell upon vaas sparrow and his crew of scallywags

thanks for reading i hope this was usefull
and note:
these are recommendations and suggestions