Rather than reinventing the wheel, it seems best to just reuse the DCC classes for Space Crawl where appropriate, perhaps lightly re-skinning them to make them fit an SF setting.
- Warriors – any sort of soldier, marine, ship’s gunner, space ranger, etc. that doesn’t rely on high tech powered armor like a Trooper does. Also, any sort of barbarian world primitive warrior. Just swap out most of the archaic weapons for modern firearms.
- Thieves – any sort of thief, smuggler, rogue, con-man. Remember that thanks to the AI war, most security systems involve physical locks and traps rather than hackable biometric scanners and computer pass-codes (if you don’t want to use the AI War and its consequences as part of your setting, just substitute high tech security systems for the equivalent Thief skills). For cast spell from scroll, substitute a Science skill of the character’s choosing, using the die indicated by the Thief table.
- Halflings – re-skin as Plucky Kids. Replace Infravision with Nose For Trouble: plucky kids have an uncanny sense for when they should sneak off after somebody who seems suspicious, or just interesting, to them, or wander off into places they’re not meant to go. The Judge should indicate to the Plucky Kids when their Nose For Trouble indicates something interesting (much as for Dwarves smelling gold), and if the kid chooses to follow the hint, the rest of the party has no chance of noticing the kid is gone until some time later of the Judge’s choosing. It’s bad form for Judges to use this to lure the kid to get killed outright.
- Clerics and Wizards are not appropriate for Space Crawl, though Scientists occupy a similar roll to Wizards. A character might be some kind of preacher or clergyman as a background, but no powers come attached, and if there are Gods in the cosmos, they take a far less obvious role in the affairs of mortals.
- Elves and Dwarves could be re-skinned as alien races, but that seems like more trouble than it’s worth at the moment, unless you want a 40K-like setting.