On the minimap, zoomed in the whole way, 100 meters is between 1/4 and 1/3 of the width - closer to 1/4. You could actually place base structures a bit closer - technically 81+ meters but.. no way to measure distance that exactly.

At this point, gearing up and moving into position to kill off Elder, I'm pretty much running 'no-base' Really I have a base.. sort of.. but it is just spread of a few hundred meters so it doesn't count lol.

It may sound like I'm going to a lot of trouble to avoid having a base but really the opposite is true. No raid defenses being necessary, even to the point of finding a flat area to squeeze everything into - huge time & grind savings.

Where I can't find a suitable ruins to modify, I just build on stilts - I mean I use small buildings, mostly 3x3 or a bit larger if cart garage included, others like temporary construction/rest shacks are just 2x2..

Much depends on the map. If I have long stretches of water travel without any handy islands for stop overs, it is going to mean packing up all the necessary bits & pieces to rebuild the necessary stations. Until longships this is a rather land bound strategy.