So as a Vermonter I can speak to a lot of this. Yes we import a lot of electricity but that's mostly because we shut down our nuclear power plant a couple years ago. Depending on the situation with the fuel rods & etc it could be started back up again with some effort. We also majorly underutilize a lot of our hydroelectric dams. They're there, but not generating power at maximum capacity.
And it isn't like we can't build more. Vermont has a pretty robust green power industry that's constantly making more solar and wind farms. And it isn't like we're going to have a problem with electronics. Global Founderies, what used to be IBM Burlington is still a major manufacturer of microchips and has a large population of chip engineers so that we could design and build new devices as needed. It isn't a 6nm line like AMD is doing over in Taiwan, but non-cutting-edge electronics manufacturing is better than NO electronics manufacturing. Biggest obstacle there is going to be the loss of the chemical imports for things like photo-resist and all the acids used in the various tools. Most of those were imported from out of state, but UVM has a pretty solid chemical engineering department so it isn't like the institutional knowledge would all be lost. Power is another issue as from what I remember, that chip fab accounts for something like 12% of the power consumption for the entire state. I'd expect it to be declared a strategic resource and limited to producing solar panels and a supply of replacement electronics for things like the hospital infastructure and military electronics.
From a military standpoint, Vermont is briefly the new superpower. We may not have a huge population, even for the era, but we have massively overpowered force projection capabilities thanks to the VTANG and their shiny new F35 squadron. A couple of C-130s and Blackhawk helicopters also base out of BTV. We also have a smattering of tanks spread out across the state at various places like the Lyndonville armoury and Camp Johnson. General Dynamics has a presence up in Jehrico where he 10th Mtn Div bases out of, but I can't speak to how much R&D they do there, I think it is mostly just weapons testing. Granted this is a force with a very short half-life due to logistical constraints, but just a couple F-35 show-of-force strikes against the British could well force a surrender because the Brits wouldn't know that they're basically a bluff. Although it is worth mentioning that said air guard base has its own fuck-huge fuel tank for the jets, although how long that would last and at what operational tempo is not something that I can answer.
Also in terms of crop production we make a boatload of corn, but it mostly gets turned onto silage for the dairy cattle. With the need to balance our dietary regimen, a lot of that could easily just be swapped over to eating instead.