Here's a few pics of my set up from my trip through South America back in 2013-2015.
As others have said the considerations for long term trips are a good bit different to a couple of nights out in Wales or the Peak, as there needs to be an added layer of comfort and practicality given the often shifting nature of your requirements based on each country.
Tetris like packaging becomes tiring pretty quick
On my trip I opted to use Carradice luggage due to its bombproof nature, and ability to repair easily not to mention its volume capacity.
https://www.instagram.com/p/BAerfrqOP0o/
My Ogre (pictured left) was pretty laden in the early part of my trip, in hindsight my framebag was too small before I learnt the value of custom made framebags with plenty of front flair.
https://www.instagram.com/p/zci-SuOPxX/
Here's my Pugs in Ecuador toward the later part of the trip, I'd swapped bikes by this point and paired back on quite a bit of kit to dial in the set up for Bolivia, Peru, Ecuador and Colombia where I predominantly rode as much dirt with plenty of hike a bike thrown in.
Where practical I'd always recommend running tubeless, and would normally favour using meths stoves over multifuel given the simplicity of the stoves, with a bit of searching you can normally find alchohol of some variety to use - in South America they often drink the stuff you use to cook
Myself and my girlfriend are beginning to plan another trip away, and this time round I'll most likely to favour a lightweight rear rack, micro-panniers and a seat pack to offer a fairly flexible configuration if we decided to stay somewhere and do some short overnights combined with a framebag and front harness.
Enjoy your trip wherever you get, there is something magical about travelling by bike for extended periods.