Our first TT was a 20 footer. Could easily tow it up and down the lanes in a Walmart parking lot and even park it end to end. First trip out to a local CG only a few miles away was a white knuckle,sweaty palm experience.
Now have a 29 footer. Length no big deal. Mostly just a different "feel" to it that you get used to fairly quickly. It's actually a little easier to back up. Try backing up a lawn tractor with a little trailer behind it. Have never once had an issue getting in/out of a gas station or finding a spot in a CG. You can def. feel the extra weight but a non-issue with the right tow vehicle. If we have to stop for groceries somewhere, we go straight out to the very back of their lot. I love towing this thing and there's no place I won't take it!
I would say with a longer trailer it's all the more important that you address all the things that can reduce sway and improve handling - tire pressure, WDH type, WDH adjustment, TT level to slightly nose down, etc. We have zero sway and feels like a sports car on twisty mountain roads at speed. :)
Going to 29 footer gave us all the things we wanted like large walk-in shower, slide with sofa, bedroom with door, large kitchen counter (rear kitchen model), large closet in living area and a few more that our 20 footer didn't have. Major improvement in creature comfort. :)
'Course, no TT can remained untouched from the factory. Have done many mods and as far as creature comfort goes, the Harrison double recliner with power recline is #1. Better than what's at home, lol. To watch TV in our little 20 footer, either had to sit upright on a dinette seat or in bed. Got tired of that pretty quick.
