Here is a good place to start researching the nitty gritty to start getting equipped for bigger trips with required gear... it is pretty much the jammy. these guys did a great job explaining how to get after it...
Self Support Kayak Camping
I personally dont have a camping boat yet (xp, traverse,katana etc..) but did fit 4 days worth in a Superhero easily (any good size creek boat pretty much will work...) ... be careful planning on overloading small boats...obviously the performance changes drastically..
So consensus is that the best stern specific drybags are watershed futa stowfloats, but also the most $$$$. they are very durable tho.
NRS stowfloats are more budget friendly.... and less bomber, and different way of sealing that seems more prone to catastrophic leakage. (roll-up vs zip)
2 of them in the stern and 2 xsmall dybags up front in front of your feet, 1 small watershed bag strapped inbetween the legs, and a 1L of bourbon instead of 17 cases of beer... and then think packing ultralite like a backpacking trip.. thats the basic basic setup, if you dont have to worry about a groove tube.
obviously a lot more to it, but some preliminary idears to help get you pysched...
self support kayaking opens up the frontiers for long trips..
i am definitely looking forward to getting out more in the future..