In terms of a middle ground between fat bikes and "normal" off road bikes, the Surly troll looks rather nice. It'll take a 3" tyre on the front and a 2.8 on the rear (why they didn't allow for 3" rear I'll never understand...).
As for how to carry luggage. I would take a look at how People like Helen Lloyd, Emily Chapel, Sarah Outen, or Lee Craigie carry luggage. Helen has cycled the length of Africa and crossed Siberia in winter (She wrote about them in
Desert Snow &
A Siberian winters tale). Emily Chapell has cycled over half way round the world and won the Transcontinental race this year (More on her in
What goes around). Sarah Outen circled the world by human power, including cycling across Eurasia, and then crossing North America in winter (Her Book -
Dare to Do). Lee Craigie Rode the Highland trail 550 this year.
All 4 rode very different terrains, on very different bikes. All 4 didn't use a trailer. Emily used a fat bike for her ride across Alaska in winter, Sarah did it on a Thorn touring bike. Her TCR ride was done on a road bike with Apidura luggage.
There's a lot to be said for the traditional 4 panniers and a handlebar bag, it spreads the load so it's nice and balanced, you can keep things organised, and you have well over 50 litres of luggage. But it can lead you to packing more than you really need, because you have the space. That said in winter I'm not sure you'd be able to carry enough stuff by the time you put a winter sleeping bag in one pannier (if it fits). That said you need to do more mods on the bike in winter as the grease in normal bike parts freezes at -20°C.
The other option that seems to be increasing in popularity is "bike packing" luggage. I really like the idea of it and will certainly be getting some on my new tourer once I've finished building it. It has the nice bonus of keeping all of the weight in the plane of the bike. But it can limit how much stuff you can take, as well as compromises if you have drop handle bars, or a compact frame.
This then brings us onto the question of "locations". The obvious direction would be Scotland plenty of trails, lots of open access. In the truly remote moorland you may want to rethink the hammock choice tho, not many trees on top of the mountains...
The other option I would suggest is the Netherlands. Sure it's not known for wilderness... or mountains... but it does have some rather pretty areas, great cycling potential *AND* there are options for free wild camping (Let me know if you want more info on this).
Failing that, get on your bike, pick a direction and ride.
Just remember, rubber side down.
J