Not strictly TM-related, but I found I-93 widening through Concord and projects to widen and add AET on the Everett Tpk of interest...
The big one which I've been aware of previously and also impacts Vermont: a new VT/NH 119 bridge is being built about a half mile downstream of the existing bridge. I don't know of construction has begun yet, but I know it will by next summer because there's a 3-month closure of VT 142 at that time where the new bridge will tie in (which requires elevating 142).
(EDIT:) I've found news articles that indicate the bridge will be completed in 2024.
Another big one: construction of "Exit 4A" on I-93...a new interchange about a mile north of Exit 4. Looks like construction in the 2022-23 timeframe. Project website is inactive, but there's a
project info page on NHDOT's website.
I did find 2 projects that might involve TM changes: there are plans to rebuild the I-293 interchanges at Exit 6 and Exit 7. Depending on which options they're going with, it might require changing points and possibly changes to NH 3A. A while to wait though, as funding isn't identified for construction until 2027.
Also a potential realignment of the NH 107/NH 150 intersection but that one's even further out: 2030.
Potential reconfiguration of the US 202/NH 124/NH 137 intersection in 2023.