The James J Hill House and Alexander Ramsey House are mansions from more than 100 years ago. You can visit them anytime, but they are decorated for the holidays after Thanksgiving.
The Minnesota State Capitol is located in St. Paul and is where much of the work of government happens. It's also a beautiful building to visit and take a tour.
A fur trader's fort can be explored in Pine City. The North West Company Fur Post is where French fur traders, Native Americans and business men met to buy and sell their wares. An early shopping mall?