Maybe if baby is 3mo. If a woman had no problems riding roller coasters before pregnancy, she should be ok to ride again by 1 month after delivery, unless she had surgery or back problems, etc..., in which case she should check with her doctors. For maximum baby safety, parents should avoid bringing home germs (viruses caught through contact with other people) and/or visitors until a baby is over 2-3 months old.
Depends. After a normal birth it takes hours to weeks to recover. If you are breadtfeeding well and bleeding less than a normal period flow, you can enjoy any activity that doesn't exhaust you or increase your flow. Prolonged standing and walking may be a bit much. You also don't want to be around smoke or germs or be away from your newborn for long. If you had a c-section or had complications, check first.