Welcome, John, from a fellow Wahingtonian (top LH corner). I'm not a TT guy, as you can see from the signature rig, bit a couple of friends have lightweight TTs that they pull with vehicles similar to yours.
My neighbor across the street has a very unusual TT. It's an "Oxygen" trailer, a very narrow track device, all Fiberglas and aluminum - no wood anywhere, even in the furniture. It was made by a Canadian company who are out of business, but there are some used ones around. He normally tows it with a Chevy pick-up, but he also has a hitch on his 1941 Chevy sedan.
More common lightweights are Casita and Scamp. We know people who have both. I'd suggest doing the weight calculations on what your Mariner can tow, then go looking for the most TT you can get within its limitations.
Frank Damp -Anacortes, WA,(DW- Eileen)
ex-pat Brits (1968) and ex-RVers.