I imagine that the density of the gas in the protoplanetary disc around a young star would vary with distance from the star.
I note that the atmosphere on Mars is quite thin compared to that on Earth:
The average surface pressure is only about 610 pascals (0.088 psi) which is less than 1% of the Earth's value
But there are sometimes sandstorms on Mars, and airborne sand and dust does settle on the solar panels of Martian rovers. So the winds on Mars might be felt through a spacesuit.
The atmosphere on Triton, the moon of Neptune, is much thinner than the atmosphere on Mars.
Triton's surface atmospheric pressure is only about 1.4–1.9 Pa (0.014–0.019 mbar).
The surface pressure is only 14 microbars (1.4 Pa or 0.0105mmHg), 1⁄70000 of the surface pressure on Earth,1
In 1989 Voyager 2 discovered that near the surface there are winds blowing to the east or north-east with a speed of about 5–15 m/s. Their direction was determined by observations of dark streaks located over the southern polar cap, which generally extend from the south-west to north-east. These winds are thought to be related to the sublimation of nitrogen ice from the southern cap as there was summer in the southern hemisphere in 1989. The gaseous nitrogen moves northward and is deflected by the Coriolis force to the east forming an anticyclone near the surface. The tropospheric winds are capable of moving material of over a micrometre in size thus forming the streaks.
The atmosphere is dense enough to allow the formation of dunes.
So it is possible that even an interplanetary atmosphere as thin as the atmosphere of Triton would have visible effects.
A meteoroid is a small rocky or metallic object in outer space, ranging in size from a grain of dust to about a meter in diameter.
When a meteoroid, comet, or asteroid enters Earth's atmosphere at a speed typically in excess of 20 km/s (72,000 km/h; 45,000 mph), aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor or "shooting star". Meteors typically become visible when they are about 100 km above sea level.
Meteors become visible between about 75 to 120 km (250,000 to 390,000 ft) above Earth. They usually disintegrate at altitudes of 50 to 95 km (160,000 to 310,000 ft).3
So gas as thin as Earth's atmosphere at altitudes of about 5 to 120 kilometers would cause meteoroid's passing thorugh it to glow with the heat of friction and even disintigrate.
If you were standing in such a dense interplanetary gas you would see meteors as passing meteorids glowed with heat, especially since the protoplanetary disc should have contained many times as many meteroids as interplanetary space now has.
The interplanetary dust grains would be slowed down by collisions with gas particles and would spiral in toward the star. And they would be broken down into smaller particles, and so would have a hard time clumping together to form larger particles and eventually planets.
So if the gas in the protoplanetary disc was even as dense as Earth's atmosphere at altitudes of 50 to 120 kilometers, astronomers would have to include that in their computer simulations of the formation of the solar system.
So how dense or thin is Earth's atmosphere at altitudes of 50 to 120 kilometers?
The scale height of Earth's atmosphere is the height difference where the density of the atmosphere decreases by a factor of e, about 2.718. It isabout 8.5 kilometers.
50 kilometers is a littles less than 51 kilometers, 6 times 8.5, while 120 kilometers is a little more than 119 kilometers, 14 times 8.5.
Accordign to my rough calculations at 51 kilmeters altitude the density of Earth's atmosphere compared to sea level is about 1 divided by 403.17787, or 0.0024802, and the density of Earth atmosphere at 119 kilometers compared to sea level is one divided by 1,201,004.7, or 0.0000008.
And i expect that a much thinner interplanetary gas would have significant effects on the orbits of interplanetary dust particles over thousands and millions of years as a solar system forms.
So theories and calculations and simulations of planetary formation should probably include estimates of the density of interplanetary gas in those eras and its effects on dust particles.