Here's an update on the stripped coupler bolt I was struggling with. After reading that some people managed to get them out with Torx heads, I went to the local hardware store, bought a T47 insert for 1.99, and taped it into a 1/4" socket for a 1/4" drive.

However, since it would have been impossible to get enough torque on that bolt with a 1/4" drive, I used a 1/4-3/8" adapter, a 3/8-1/2" adapter, and a long, 1/2" breaker bar to loosen the bolt from inside the cabin, after turning the wheels so that the bolt head was facing straight down and carefully torching the threaded part for a few minutes.

Still, I thought for sure that the Torx head was going to slip at any moment. So I had an EZ-Out and a drill bit ready to try when it did.

Much to my amazement, though, the Torx managed to get enough bite on the stripped bolt head to withstand the amount of force I had to exert on the breaker bar to finally loosen the bolt. Boy, was I relieved.

Thanks again for your suggestions and the concern many of you expressed.