Nauvis - main base is fully enclosed with walls, flamethrower and gun turrets. Before this I've definitely set up a mall, nuclear, and roboport coverage.
Any planet - I want a ship for myself and ad hoc requests that can definitely get to and from Nauvis without supervision.
I'm playing the current save relatively chill, so I'm moving off secondary planets when that planet's science setup is self-sustaining, and Ive got most the research I want from there.
Between the first two requirements I can drop myself and what I think I want to a planet, send the ship to Nauvis or other, mess around a bit, and request some more resources from the ship when I realise what I'm missing.
Ive done vulcanus and fulgora and am starting gleba, for reference.
Taking it chill includes side quests like supplying a stupidly big artillery battery on Nauvis.
Kinda true. You'll want good defenses in place with bots set to repair before you head out, but there's also nothing stopping you from shipping all of the components to build another rocket silo on the other planet as soon as you drop.
You can only leave a plant via a rocket. So when you get to a new planet you are stuck till you make enough resources to build a silo and launch a rocket. Or you take the resources to build the silo with you.
Once you are on a new planet you aren't starting from scratch, you can always send stuff from navis and deliver them to where you are.
Once you have Bots and all things automated to build assembling machines run by bot logistic automated you can leave. You can then build everything remotely. But's i a good idea to have the base in a "healthy" state and able to provide you with some extra resources in the beginning. For that you of course need a ship/platform that can reliable travel between nauvis and the first planets. That ship can also take you back once have built a rocket silo on the new planet.
One suggestion for securing your base before leaving is to make a construction tank. Tanks can be driven remotely and have equipment grid. You can put personal roboport in there and use it as your clumsy impersonation for building outside your roboport coverage from anywhere.
Also, this is not explicitly stated but you do not need a cargo landing pad to drop cargo. Cargo will simply crash land around the original spawn on the planet. So no stress building the first cargo landing pad.