The highest-rated panels do about 200W/sqm.

Very roughly, it looks like the prius has a 1.1sqm hood, 1.7sqm roof and 1.1sqm trunk. That's 750~775W worth of panels.

The prius has an EV range of 25mi with an 8.8kWh battery, that's 2.8mi/kWh, so with the 3.9sqm worth of high-power panels above and assuming full sun (full power production) you'd gain a range of 2.17mi/h.

If you assume 100% efficient covering the entire vehicle and you live in a sunny area and are always parked and moving in the sun and not shade, its kinda sorta worth it.

Yes.

You did not specify the time duration, though.

Maybe when parked additional solar panels could “deploy” out of the trunk/frunk?