Sure, regular traffic can get closer. Canny Captains may thread a Reef Pass, then navigate the ever-shifting banks, tidal channels and islets of an estuary or wide lagoon.
The analogy holds good for OverSpace. Approaching in the plane of the ecliptic, with Ephemerides fresh and OverDrive tuned to concert pitch-- Yes, a well-handled ship can ride a Lo Road's equipotential manifolds to the inner planets' Lagrange Zones. But, miss the inlet, misread a grav-buoy's code, fudge any turn, snag a comet or RealSpace craft-- Pauli's exclusion principle splashes you across a thousand miles in a flare-hot gamma burst...
Without that local knowledge, you must BreakOut at the g-well brim. To get in-system before locals rise in arms, you must move real fast. A tenth g boost requires 50 days, a quarter 32, a 1g boost 16-- All much too slow. Even with anti-matter fuel, a big ship straining frames and crew to pull 3g still takes a dozen days. To better that, you gotta bring a heap of delta-v.
The People's three vast ships ram into RealSpace at almost one-tenth c. At such speeds, the solar wind is a buffeting gale. Hard vacuum holds enough trace gas to seem sand-blast. Dust-grains strike like cannon shells. Each pebble is a TacNuke. Perforce, such ships must deploy layered sweeper screens. First, smoke to clear zodiacal dust, to high-light pebbles and larger for the point-defense. Chaff smites gravel, blinds hostile sensors, may dissipate beam weapons. Smart Pebbles wait to throw themselves against glimpsed mine or rock. Ship-killer / point-defense missiles fill a navy's Cruiser role. Hardened sensor probes peek around the smoke and chaff, don't survive long. Semi-autonomous replenishment drones work to fill in the gaps.
Each ship's screen rips a path through interplanetary dust, is consumed to leave a weird comet tail. The three ships' triple bow launchers cycle steadily. They feed replacements forwards, as coldly, inexorably, as foot-soldiers to a great battle.
---
FWIW, Martin Lo is real.
Interplanetary Transport Network - Wikipedia, the free encyclopedia