Invariably , the cars that aren’t strong sellers initially, or are not received well or that are just underproduced ..often become sought after classics. Automotive history shows that . Not always , but often . The Lj fits that category .
As said earlier...you know this Jeep. It'll be a craps shoot with a new(different) one. It could end up costing $thousands to undo what has been done to it. Keep the LJ. It's family to you. And they are (supposedly) better in the rocks anyway. Either way we'll be here for you man.
How much is a trailer in your area? I don't see the rationale as your undoubtedly going to have to put some not so little money into a new TJ to get it where you want it. That could easily eat up the cost of a trailer. I'm guessing here. As I have not priced out trailers in years. But still. The cost of getting an older cheaper TJ up to trail ready use only. Is going to be substantial.
You also have a known quantity in your LJ now. You've owned it long enough and done enough improvements that you know what you've got. Hard to determine that in a used TJ. I'm assuming that you're happy with the life your LJ has had so far. Not abused. Maintenance kept up. And you've probably gone thru and replaced enough stuff that you know it's going to live a long and happy life.
The only reason I can think of to switch from an LJ to a TJ is getting in and out of tight spots. So if you have a trail or trails you want to run that lend themselves to that advantage in a major way. I don't see an advantage in switching from an LJ to a TJ.
But it's also hard for us Jeep TJ/LJ fanatics to seriously consider getting rid of an LJ. For a probably less nice TJ and trailer. I say save up for a trailer to tow your LJ. And start improving it as money allows. And if your like me and prefer to go on days long journeys. Rather than day trips. That LJ will be alot more hospitable. More room. More length. Etc.
I'm in your boat. I've thought about leveraging the value of my LJ to build a TJ. In the end I like the added stability of the longer wheelbase and the extra room so I've stuck with the LJ and save for my tweaks. They are really more alike than not. Most people go TJ -> LJ but who cares where the herd grazes.