Yes, you can definitely bake potatoes and baby carrots along with your roast at 350°F. Just keep in mind a couple of things for best results:

1. Size matters: Cut the potatoes into even pieces so they cook at the same rate as the carrots and roast. If you leave them whole, they may take longer to cook than the roast.
2. Timing: Depending on the size of the roast, potatoes and carrots might need to be added partway through the roast's cooking time. If you're cooking a smaller roast (like a 3-4 lb), you can add the potatoes and carrots in the last 45-60 minutes. If the roast is bigger, you may need to add them earlier.
3. Seasoning: Toss the potatoes and carrots with a bit of olive oil, salt, pepper, and any herbs you like (rosemary, thyme, garlic, etc.) before adding them to the pan. That way they’ll get some nice flavor and caramelization.

If you're roasting a big cut of meat (like a whole roast), you can also place the veggies around the roast in the pan, so they absorb all the tasty juices.