We tried playing with these rules mods last week, and it was pretty good. The idea was to test both the August 2012 D&D Next playtest pack and to see if my very rushed, crude Spelljammer adaptation would work with that, and the short answer to the latter is "yes."
Toril. The plot was basically: Drow pirates have found a treasure asteroid; Drow pirates are chased by goblin pirates and both crash-land within sight of the player-characters' village; Players get to seize the goblin ship (which had a serious helm fuck-up, presumably because of goblin stupidity) and salvage the working helm from the drow ship (which was simply shot down by the goblins), along with maps and instructions on how to work the ship and reach the asteroid; Players get to battle other drow ships defending the asteroid and then claim its "treasure".
|Dockhill, players' map|
|Dockhill, GM's map and adventure notes.|
You'll note I picked a couple of monster races that are pretty uncommon in Spelljammer, simply because they're among the few already prepared for D&D Next. Since my players have never done a real Spelljammer campaign, I don't think they noticed this. I gave the goblins (and thus the PCs) a squid ship and the elves a squadron of man-o-wars, figuring I'd follow the standard low-level dungeon model of players versus a larger number of relatively weak foes, allowing for a longer but more survivable combat rather than a fairer one that's over too quick.
Initially I was worried that the more manoeuvrable man-o-wars might be too hard for the players to out-turn, but they learnt very early on that their squid could tolerate rammings far better, and whatever numerical advantage the drow began with was negated, first by my players sneakily creeping up on the asteroid while the orbiting drow were out of sight on the far side of it, giving them a surprise engagement against the first lonesome drow ship, and then simply smashing into and instantly wrecking one of the pair that followed after; the damage they took from ramming was probably less than they'd have taken from a pair of nimble man-o-wars fucking around with them for several rounds, and it certainly sped things up a lot. I had to throw in that third man-o-war just to make up for how fast they were slicing through the flimsy elven hulls. In hindsight, I should have made that extra drow ship something bigger (another squid, I guess, since that was all I had prepared and with me at the time), just to see how a more even combat would have gone.
The spelljamming mage insisted on an 8-hour rest before entering the asteroid, so he wasn't fully dependent on my 'Minor spells remain in play' rule, but during their few ship-to-ship boarding actions, he did benefit a lot from being able to do anything useful at all.
The main point is, nothing about the gameplay seemed terribly wrong, so I guess my rules mod will work fine for now. The D&D Next core mechanics still seem really good, but the players had a lot of concerns about the new character creation rules, which seem pretty inflexible and chaotic, which is an odd combination. Hopefully they'll rebuild that for future test bundles. I like the pre-made Backgrounds, but maybe not the Specialities so much.
|Lost Boon, players' map|
|Lost Boon asteroid, GM's map|