As much as the scenario (1) fun wants me to say the characters will end up inside the sphere when they hit the solar 100d I think the (whatever - mass, density, gravity) of the shell itself will precipitate the ship before they enter it for different scenario (2).
Ah, but what would be the 100d point for that shell? How thick is the shell will answer that. If it's a shell thick enough to generate 1G natively then it'd be about a World Size 8, unless other steps are taken (3). A World Size 8 thick shell would also have 1G on the outside which would be interesting in itself. Not as useful as 0G though.
I'd probably go with World Size 0, jump precipitation outside the sphere, and make the approach dicey and exciting. As in if the players are approaching with a high delta-v (pretty much anything more than zero), the thing fills the whole sky when they drop out, there's no way to "miss" it and it looks like they may very well land quite hard. How hard will depend on how fast their incoming vector was... but some might find splatting the characters and ship evil
(1) Where did the stars go? Where are we? No way to know unless they can get "outside" to get some bearings.
(2) WOW! Lookitthatthing! How do we get inside?
(3) For reasons of strength of materials and limits of raw materials (4) a thin shell will be likely so it could (should) be less than a World Size 8. I'd probably rate it a World Size 0 just for simplicity. BUT... you'll have to have artificial gravity then. The benefit of a Ring over a Sphere is you can use spin gravity so you don't need the extra mass or artificial gravity generators to create a decent gravity.
(4) I recall reading ages ago that a simple, very high tech (thin) and narrow Ringworld for a Sol type star would use the material resources (mining and processing ALL the planets) of more than a single Sol type system.
o:
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