What is the max length travel trailer you think is practical

The best size TT for us has been a 25 ft. Dutchmen with a short slide. It is just my wife an I and a big dog. We tow 5000 to 8000 miles a year mostly State of Fed parks or recreation areas. The TT always fits the campsite, can be pulled with an F-150 and is small enough to wind through city streets to find the next museum or quilt shop.

We come from a tent and canoe background, our TT is the lap of luxury.

Your needs my vary. Rent one to find out.