Newbie Titan researcher here! I was wondering about this same question, but there are a few papers that have since answered your questions. I'll summarize their findings below:
TLDR: For an astronaut, the sunset would be quite underwhelming, much like being in a sand storm or thick smog. The sky will have no real change in its orange color. The Sun disappears well before reaching the horizon. You will need infrared goggles to see better sunsets.
Overall, we actually observe that the twilight periods (sunrise/sunset) are brighter than the day on Titan from infrared to UV wavelengths due to the intense forward Mie scattering from the haze. This finding was found with Cassini images in various wavelengths (Garcia Muñoz et al. 2017) and confirmed with radiative-transfer models (Barnes et al. 2018).
The models of Barnes et al. 2018 provide useful insights into a standard sunny day on Titan. This figure shows the Sun setting from early afternoon and until after dusk in visible, near-infrared, 5 micron light. The image shows a "rolled-out" version of the sky as seen from the surface of Titan. The leftmost column shows the Sun and progresses toward the antisolar point to the right side. The top and bottom of the image are zenith and the horizon respectively. The ZD represents the angle between the Sun and zenith. The first diagram below explains the format of the "rolled-out" sky images in the 2nd figure:
We can note some key details about the sunsets:
- The 5 micron sunset is very similar to Earth due to the similar atmospheric optical depths of Titan at 5 microns and Earth at visible wavelengths.
- In the near-infrared, the sunsets resemble a Martian (PIA07997) or dusty terrestrial desert sunset. There is a distinct solar aureole that transitions color from white to "red" over the afternoon. The Sun would fade out just before it sets (<10° above the horizon). The interesting new detail is the fan-like aureole that develops above the Sun!
- The visible-light daytime and sunset might be quite disappointing for astronauts. The sky would be faintly and uniformly illuminated during the day, similar to looking through thick fire smoke on Earth (no issues with staring at it!). The sky would have a nice orange hue that just slowly fades away as the Sun nears the horizon. The daytime sky is likely 100-1000x dimmer than an afternoon on Earth.
Another crazy detail is that the twilight zone may extend 30° past the terminator line. This means that the surface visibility at infrared and visible wavelengths will be brighter than the full Moon for up to 1.25 days before sunrise or after sunset! This is about 20x longer than the usual twilight period on Earth.
One final result from the paper was the intriguing lack of near-horizon illumination at all wavelengths and times of day. On Earth, the opposite occurs due to Rayleigh scattering and its lower optical depth. However, this effect may be occurring since the paper explicitly did not consider Rayleigh scattering from liquid methane-ethane droplets.