If the trailer is balanced with slightly more weight on the tongue, you don't need 'bags or springs'. 200-lbs of tongue weight is excessive.
If you're simply bopping around Michigan, Ohio, Indiana, Illinois and Ontario, electric brakes are optional because we are flat and at sea level with a few mountains 'up north'. The guys climbing the Rocky Mountains or the Appalachians need brakes, carb jets, etc. Michigan weather is very mild compared with the California desert (or the Mojave), so a decent stock cooling system should be good enough.
We see six and four-cylinder vehicles pulling trailers all the time, here. By comparison, your Thunderbird is a monster. - Dave