I double majored in psychology & sociology at UVM, so I can answer your questions. The psychology department takes itself a little too seriously for my liking, they spend so much of the intro classes telling us why psychology is a science, that I wondered who they were trying to convince. The sociology department is wonderful. If you have a chance to take classes with Brookes Cowan, Laurie Essig (who may have moved to a nearby college, I'm not sure), or Jeff Haig, go for it! They were my best professors ever. Steer away from Robbie Kahn, as all her classes (regardless of subject) devolve into discussions on childbirth, complete with videos. Also, Herb Leff's classes seemed a little wishy washy to me - too much feeling, not enough thinking.
So long as you realize that the rankings are biased by those who either loved or hated the profs, check out
RateMyProfessors.com for more recommendations.
UVM does not allow firearms on campus. In fact, I think it's cause for arrest. There is a Shooting Club, but they maintain their guns at an off-campus storage facility. The rest of Burlington (if you rent) has pretty liberal gun policies, including concealed carry. Check out the laws before you do it though, as I'm not an expert.
You can get your transfer credits approved before you decide to transfer. Be sure that everything you think will transfer will transfer because no one wants to spend extra time at university, especially not one as expensive as UVM!