On Spelljamming and Speed

So, space is huge.  Ludicrously so.  This creates a big issue for spaceship (or spelljammer) stories - the "cruising speed" needs to be high enough for many interplanetary or interstellar voyages to occur during your story, but you also want naval combat to look good on screen and maybe even resemble naval warfare from a certain historical period, so the "tactical speed" needs to be low enough for that to work.  Different properties have resolved this in different ways, but very few of them have been satisfying.  Most movies and television series pretty much ignore the issue within a single star system while including some sort of warp drive to get between systems in a reasonable amount of time, while books (especially hard sci-fi) tend to go ahead and deal with relativistic projectiles and whatnot, because that's more interesting to read about than a dumb excuse for staging a traditional naval battle.  However, neither of those plans really works well for D&D in space.  The movie/TV solution doesn't work because the player characters need to be able to make decisions and reason about the time it takes to move around a system - if you try to handwave it away, there's an inconsistency in your game that they'd like to exploit.  The hard sci-fi book plan doesn't work because, well, the whole point of the exercise is to let your D&D characters ride around on the ship from Treasure Planet and have swordfights with the dudes on other ships.  Spelljammer's resolution to this is to have tactical and cruising speeds be explicit, associated mechanics - i.e. the PCs and the players have the same understanding - if there's nobody near you, you get to move at cruising speed, but if there's another large object nearby (for some definition of large and some definition of nearby), then you can only move at tactical speed.  How this works for fleets is never really explained, and the problem that space is REALLY BIG and therefore there's no such thing as "random encounters" isn't addressed (there can be encounters that the PCs didn't intend to have, but the odds that somebody just happens to be within a few miles of the PCs are ridiculously tiny - all close encounters in space are ones that somebody wanted to have).  I'm not really sure what the right resolution to this is - Spelljammer may have gotten it closer to right than anything else I'll find, but it would be nice to have something that allows for truly coincidental random encounters while letting both reasonably short interplanetary travel and boarding actions happen.