Yes, that's about right. Most veg are very low in calories and they contain loads of vitamins and nutrients to keep your body healthy so include as much as you can. Just make sure that you're not roasting them with loads of oil as this pushes the calories up by a lot (135cals per tablespoon). Exactly the same advice goes for roast potatoes, don't cook them in oil. Instead you could use a spray oil like 'Fry Light' at 1 cal per spray.

Sweet potatoes are great baked in their skins, no oil needed. Swede..? not sure how to make it taste good.. mashed cauliflower is also a great substitute to mashed potatoe.