My wife and I took a short ride on the Minuteman today out to Lexington - her first ride of the season. Had not been that way in a few weeks, and I was surprised to see that the Lexington visitor's center on the path is closed for the coming year. Plan your restroom breaks accordingly.
There's not much info about the remodel on the town website:
https://www.lexingtonma.gov/visitors-center
It would be nice if the new visitor's center had externally accessible restrooms like the ones at the Bedford Depot, big enough to bring your bike in with you. That's very handy when riding solo without a lock.