Around my house, it's a sore subject. As was said, it varies widely from city to city and county to county. The closer to a major city, the higher they go. All told and best I can figure out, my tax burden was a far less living in Florida compared to Alabama.
The property taxes on vehicles are all over the place depending on your vehicle and where you live. The state determines the value of your car based on year/make/model/trim and then feeds that in to the vehicle property tax rates you pay for state/county/city. I went from registering my 2004 Crown Victoria for fairly cheap to over $300/year when I got a new Ford Ranger. If I weren't in city limits, I would be less than half that. I'm not familiar on the registration/taxes on trailers, but I figure I'll be getting there this year as I'm getting an old utility trailer from my folks.
One thing you didn't mention outright but that I would be cognizant of is property tax rates on homes. The biggest thing there being that Florida has the "Save Our Homes" amendment that was passed a long time ago that puts a limit on how much property taxes can go up every year whereas Alabama does not have such a law. When we moved to Madison City (Limestone County), the previous owners of our house had annexed into the city a couple years prior but it was still reasonable compared to what I was paying on my house in Orlando. Looking up the history, the tax bill doubled across the board (Vehicle and House) when the annexed into the city from county. With the rise in property values due to all the contractors/government agencies and other businesses setting up shop here and the votes to increase millage rates for the city school district, my (house) property taxes have gone up 75% in 9 years and I'm expecting another 10-20% bump over last year when I get my assessment in July.