A short follow up:So I've spent the past 2 weeks thinking about nothing but GURPS and Space and how to do a fun campaign.This weekend we had our first play session - two 13-year-olds and two 10-year-olds - and it went well. We spent a couple of hours creating characters, and then a play session getting into the whole concept of playing a TTRPG and completing a short scenario.Overall it was taxing but fun, the kids had a blast, and I didn't get bogged down with rules-stuff which I am prone to do. Everyone wants to play again soon, time permitting.I have to railroad them a bit more than I expected, but that's ok. As they get more familiar with the system and the whole concept of roleplaying I expect they'll soon be able to navigate on their own.