What can you safely tow and still have the appropriate wiggle room?? That's where you stop looking. And under NO circumstances let a salesman talk you into stepping one foot inside anything larger. How many do you need to sleep on a regular basis? Do you like KOA (kamping on asphalt)or a nice cozy woodsy campground. So now you know that you don't want something that's 40' because you can't get the darned thing into the cozy campground. Do you need to haul bikes, firewood, misc stuff in your tow vehicle?? If yes, a 5er is probably not what you need. Maybe a TT would be better. If you like sleeping under canvas and don't mind the extra efforts needed, maybe look at a HTT. So figure out the big stuff and then start on the details.
I agree that you're overthinking this project. The more you look, the more confused you're going to be. Our first camper was supposed to be a Shamrock 19 HTT....4 months later FR hadn't gotten around to manufacturing it because the world was buying 21SS and 23SS hybrids. Meanwhile, we changed plans and bought a 23SS and it was the perfect HTT for us. We looked at 4 trailers before we towed the 23SS home and never regretted it for a minute.
Forward 8 years and old age has sneaked in. A HTT takes a bit more work to set up and break down and DH had some health issues. Came down to get out of camping altogether or move to the darkside. This discussion went on almost a year without ever setting foot in a trailer. Last trip with the ROO was a huge PITA. Next day I went online to RVW and found THE perfect trailer for us. Still never set foot in it. DH agreed, we got a price, gave them the deposit and a few days later we were heading north to pick it up....still sight unseen. It really is "us".
Gotta sell the ROO. A darling young couple with the cutest 3 year old daughter found it listed on craigslist. They had looked and looked and only knew they wanted the right trailer for their family. A zillion pictures and emails back and forth and they bought it sight unseen. When we met them at their bank, we fully expected they'd want to at least walk through before signing, but nope....it was THE one.
Funny, but the selling feature for our new TT was the shower....DH can actually use the shower and be able to turn around. He's thrilled. Their deciding factor was the pictures of the inside of the frig (???). The whole trailer was like new, but they felt that if the frig was clean and well cared for, the rest of the trailer was, too.
This is supposed to be fun, so try not to turn it into work. Grab a cold one and a tablet and make your list of needs and don't needs, then spend some time online - cheaper than gas. Most dealers show the floorplan and inside photos. Narrow it down to maybe 4 - 6 at the most, look at those and go from there.
FWIW, RVW sells a ton of different manufacturers....also RV Direct. Both are reputable firms and have happy customers. Prices are not posted, as such, but they do show MSRP...you can guestimate the price at about 30% off and maybe a smidge more. Request a price quote and they'll email it to you. We've bought both of our Rockwood campers from RVW and recommend them highly. RVD also has a long list of good experiences reported. Or you may find what you want just a few miles away, but either the RVW or RVD price will give you some bargaining tools.
The more trailers you look at the more they all look alike, to me. Simplify. And enjoy!