Susanka, while it will be a lot of miles per day you really mention the NE and Nova Scotia as the destination.
If you hot foot it out of CO and both drive, ie like 16 hrs per day, you can reach the east coast in 2-3 long days. Not much to see between CO and NY in my opinion anyway, other than the leaves should be getting good towards the NE.
Doing this will give you 3+ weeks in your destination area which is really what you're after. Just don't get sidetracked at every attraction along the way and try to time your travel thru big cities NOT during rush hours. That and save the fuel econo driving for the tourist part of your trip and put yer foot in it on the "commute". The extra fuel $cost will save you a couple days overall.
Have fun!
