I have nuked an old side town of mine. It was around level 350, about a year ago ,I got so frustrated and overwhelmed with the rebuild that I ended up abandoning the town. It was a whole lot more work than I anticipated. I planned on going back to it at some point and fixing it up a little bit at a time, but just the thought of it scares me.
I will never do it again I would reccomend trying to do a small section of your town at a time, using the area select tool. If you have any other questions or if I can be of any further assistance, let me know or PM me.