“And I have read about the issues with the newer trucks being too tall in the beds for the goosenecks. Another worry.”
Shouldn’t be a really big worry. Of course money could be tight when it’s all said and done but it’s not like you have to go out and get a new trailer. Google “gooseneck coupler” to find a variety of options. They are basically just tubes that attach into your trailer, and I’m willing to bet if you look at your trailer you’ll find the ginormous bolts that hold it inside a sleeve. That’s kind of how I know this, because the gooseneck coupler on my old trailer was supposed to have both a safety pin and bolts. Safety pin was removed during maintenance and after a year or two that bolt loosened up just enough for the coupler to come loose. Unfortunately the whole trailer came down onto the truck and the coupler drive up through the floor of the gooseneck (right about where my head would’ve been if I were sleeping in it - heebie jeebies!!). But what I learned from that is that the couplers come in different lengths and strengths, and adjusting those dang bolts is how it comes higher or lower down to the truck.
Good luck with your shopping, I feel for you. Think of it this way, if you can afford to get even newer than what you had, then you’ll probably get some additional safety and technological features you didn’t know you wanted.