It really needs a travel map for the jetski though.
Funnily enough, I've been thinking along those lines for the past couple of weeks, although I don't believe a simple dotted-line travel map would suffice.
While the Black Sea probably boasts a decent-sized "screen count," it nevertheless ends up feeling very small. Even in the slowest jet ski loaded to capacity with cargo, every location is pretty much just a quick handful of screens away from every other location in a roughly semicircular configuration. One almost wonders why the coordinate system exists at all except as set dressing.
Furthermore, for some reason (probably the random Jet Skier NPCs and [no doubt scripted] faction patrols) I'd been expecting danger and unpredictable encounters when I got my very first jet ski. I expected to see pirates just around the corner in South Underrail, or to run into sea serpents unexpectedly in the Black Sea. You will run into sea serpents unexpectedly exactly once, but then never again. Like rathounds, they always respawn in the same spots, and if you avoid those spots, safety is assured. The pirates never seem to venture past their ports, at least in my game.
Basically, the Black Sea is a static little pond. Underrail's room-by-room structure works when on foot and when those rooms comprise a very large, many-layered, interconnected maze; not so much when aboard a fast vehicle and the rooms comprise a relatively small, mostly single-layered, open half-circle of points of interest.
I think that "faux travel" would have worked much better. Basically, in order to travel, the player would first navigate into open water, then select a heading (based on discovered coordinates, some landmark seen in the distance [described through dialogue], guesswork, at random, etc.) and "sail" toward that heading much as an actual ship would. Your jet ski would animate moving, but remain centered on the screen. After a short while, the screen would fade to black, then fade in at (or near) the desired destination, at the wrong destination/middle of nowhere, at an intervening destination (a small isle, for example), into a random encounter, or possibly even go off-course.
Instead there is a glorified swimming pool surrounded by a semicircle of pests to exterminate. Sail the high seas... for about one minute, until you reach your destination. Granted, "faux travel" wouldn't add much more DOWNTIME to travel, but it would add a greater sense of scale and a lot more room for navigational error.