I guess that I must have that 'restless spirit' because I've been playing on the same world for several months, now. Not exclusively, tho. I call it my BIGGIE world and it's been a fantastic seed for my needs.
My procedure is to start in a mountain range. Explore all the holes and caves in this range. Build a number of crafting centers in the cave system and mine all readily available materials. Make most of the caves 'habitable', connect as many together as seems worthwhile and seal off all entrances with doors and windows. Find interesting or unique features about this particular range and exploit it - this could be an especially great view or a local, handy spawning center to farm or a perfect gardening spot. Or even a couple high peaks to build an elevated glas walkway across! Once this entire mountain range is 'civilized', I'll build a roadway back to the last mountain range and perhaps a road around the new range. The roads may require building rest stops along the way so that the construction crews have shelter when caught out at nightfall or a nasty storm.
Then it's time to head out and find the next mountain range to tame... Oh, and I have to name each range as well. And it is all done in survival.
I recently checked the extent of my country and from end to end is almost 2,000 blocks long and over half that in width. Next time I play, I'll build a calendar and see just how many SC years have passed in the game... I could build like this in one world until it's so big it crashes the game. It did once and I lost some significant work so now I backup and store on external SD daily. The unpacked (internal) file is now 120MB.
I think I might upload this world in case someone loves building a civilization and wants to have a huge base with infrastructure, to start with.