Vermont's gun laws are a remnant of it's conservative past. The constitution is fairly strong on gun rights, but I doubt it would hold up to the judges we have up here now. They are very activist and find all kinds of things in the constitution that no one else can.
The last several decades have seen Vermont inundated with first hippies and now MA, NY liberals who can sell their million dollar home and buy a Vermont mansion for $300,000. In fact VT has a higher percentage of retirees per capita than any other state including FL. Where this hurts us the most is that these retired liberals have nothing better to do than run for public office and turn VT into the state they decided to leave because it was too expensive and crime laden. The rest of us have to work for a living.
The fact that gun laws haven't changed in so long is a small miracle considering the current state of affairs. Some of it might be traced to the fact that our legislature spends all it's time on the ridiculous, unimportant stuff but that's just a guess.
The gun stores I've been too have plenty of handguns. Especially those in Williston. That's where I've purchased most of mine. However you're right about there being a lot missing from the "gun culture." Instructors are few and far between and you'll never find any NRA events here.
The trespassing thing is incorrect. You can tell anyone to leave your property. In fact, you can tell who the NY, MA people are because they buy an old farm, renovate it until it looks nothing like a farm and put posted signs everywhere. (Then of course, they try to get the local government to pass laws so their neighbor who's lived there in a trailer or shack for the last 20 years has to clean up his yard and or renovate his place so THEIR new house's property value doesn't go down.)