Low milage Prius C, is taking a road trip risky?

Absolutely covered. Go for it and have a great trip. Just follow the recommendations in the manual

 

If you take I5 to Portland, then I84, you have no steep hills until after Pendleton. There is a rest area at the top, just to reassure yourself all is well

 

The breakin period for my Liftback was only 1000 km, or 600 miles. Does your Owners Manual call out anything different? Look in the Index.

If you are close to 500 miles, then take a scenic route across the Cascades, Hiway 2 or 12. By the time you get to Wenatchee or Yakima, it is done.

After that, I suggest staying on scenic routes, but for entirely different reasons.

If a scenic route doesn't fit your schedule, then just be sure to obey speed limits until past 600 miles. The climb and descent across I-90 will easily put quite variable speeds on the engine, even if you keep the car at constant speed.

 

Your new car will be broken in before you get three hours down the road. No worries.

The only consideration I recall from the break-in instructions was to not drone along at a single rpm for the first 500 miles. It is practically impossible to do that anyway. I have a scan-gauge and was watching my rpms while cruising along on level ground...the rpms were all over the place. Every gust of wind, passing truck or car, and slight incline affected engine speed.

If you don't act like you're in the Cannonball Run everything should be fine. Warranty issues that may crop up while under way would be taken care of by any Toyota dealer along the route. Keep your phone charged, get some AAA coverage, and have a ball.

I recommend the more advanced AAA coverage...RV coverage. It doesn't cost all that much, and you get more tow miles before the big charges start racking up. This could much more than take care of itself if you have one tow over 20 miles. I've used AAA several times. Fairly quick and certainly easy. Have your location, direction of travel, and geo-coordinates ready when you call. Find a place away from the traffic noises, have a pencil and paper handy, and then have patience.

 

Go to it and still follow recommended break in. Unless you do something outside legal limits or modify your Prius C warranty should cover you.