I haven't ever made the move up to a fiver, but I can tell you that you can tow a trailer without problem if you have a good hitch setup and sway control. I had a Hensley with my 29' Sunline, and have an Equalizer with our 26' Winnebago Minnie. I've traveled in quite a few crosswinds and on busy interstates with trucks, and just haven't had a problem.
Only you can determine what size unit, along with storage space will work for you. My DW and I can spend 6 weeks or longer in our trailer and do fine. Would I want to be a "snowbird" in a 26' trailer? No! But when we take longer trips, it is when the weather is nice, or we're headed to nicer weather. When we downgraded to the Minnie, we wanted the outside kitchen and that has brought us back to a more "camp like" rv lifestyle i.e. we cook outside for most meals and spend more time outside. At the same time, our dining/lounge are provides enough space for when we want to be inside, and our bathroom in the Minnie is larger than what we had in our Sunline, and probably as big as the bathrooms in many fifth wheels.
I suggest considering how long at a time you will be in the trailer, what gear you consider "essential", how you and other travelers will handle less space, and what size trailer you will look at purchasing. And, factor in how you may be able to carry more gear in the bed of the truck. If you are looking at something more than 30', I'd be inclined to stay with a fifth wheel and take advantage of the overall length reduction due to part of the rv being over the truck bed.
Finally, if you already have a 3/4 or 1 ton truck, don't get rid of it until you have pulled a trailer (if that is what you decide to do) and are really sure of what you want to tow.