My 2 year old has had a runny nose for over a week now, and coughing at night. It's not barky, but defintinely congestive sounding. Doctor trip?

Yes. Although colds can certainly linger for more than a week, age 2 is an age where foreign bodies have a tendency to find their way into the nose. At least have your child examined to make sure this is not causing the drip and congestive symptoms.
Your call. Can't make recommendations like that over the internet. Could be a viral infection, new onset allergies due to tree pollen or mold, or early asthma. If some zyrtec (cetirizine) doesn't help and the cough causes wakefulness during the night, a physican evaluation is definitely a great idea.