I guess I must be a cheapskate...
Why would you be looking at a new TT if you don't even know if you would like the camping lifestyle? I can't imagine dropping $13,000 on an new TT just to see if I like it... and that's just the initial investment. There are a lot of "accessories" needed to go along with it.
My wife and I had talked for years about getting a camper and we found a nice clean used P-up for $3000. While a P-up isn't for everyone, a LOT more work to set-up / tear-down, that got our feet wet. We acquired a bit of camping gear during that time and learned a huge amount.
We got tired of the bathhouse routine, always needing to reserve a spot close for showers / potty. We knew we wanted to continue camping so began watching for a larger one with a bathroom we could afford. Looked at a couple of used ones in the $6000 range. When we went to look at a used Hybrid that wasn't so good at a dealer, That's when we found our current one. Over in the corner was a Lightly used TT, a 2005 25 footer.... CLEAN, nice floor plan, one owner, everything worked and got it for $4500 at the end of the season.
My point is, there are a lot of nice used units out there to start out with. Let the other guy buy a new unit and take the big hit on depreciation. When he wants to sell it, that same $13K TT you are looking at would be $8000 used in the next year or two. When / if I sell my unit, I will ask darn close to what I paid.
Hang out here, learn what to look for, and shop around on Craigslist. It is full of used TT's that someone thought they would enjoy but the romance was lost once they grew tired of it.
As far as boating goes, in my personal experience no thanks I want to relieve stress, not add to it. Where I live are tons of lakes, boating is huge here. Step-Dad had a Ski-Nautic and then a Hydrodine when he and Mom were dating and I had free use 24-7. The adage "A boat is a hole in the water you poor money into" has deep roots. Maintenance costs are insane compared to a TT. There are more jack-holes on a lake than ANY campground, drunk or sober. Forget the Holidays, everybody and their brother is out on the water and most are the later trying to prove their boat is the fastest. I would get up at the butt-crack of dawn just to get out on the lake when it was enjoyable and be docked up before Noon. How many times can you go counter-clockwise around the same circle over and over before it gets boring? (Sure the same could be said about setting around a campfire I guess)
Now if you live on a Great Lake or one of the Coasts, then it's a whole different story, but now you're talking BIG MONEY!
But that is just MHO... Good luck to you and strongly suggest you try both before jumping into either one.