Welcome to FGRV, Larry! .
Lots of good information here. Some basic in formation about tow vehicle, budget range, size & features, number of people, and type of camping you intend to do (full hookups or primitive) would narrow things down a lot.
Molded fiberglass trailers run the gamut from around 13’ long and very basic to around 25’, self-contained and winter-rated. As you shop be aware that molded trailers go by overall length, including the tongue and bumper. Actual cabin size is typically 3-4’ less.
One helpful forum resource is the thread “Trailer Weights in the Real World,” with scaled weights of various makes and models loaded for travel. It’s in the General Chat section, and post #401 includes a link to a handy spreadsheet of the data you can sort and filter.
Know that supply of used units is very limited and new units have long lead times, as production is backlogged for all the molded fiberglass makers. You will have to be patient and flexible. Well-priced used units sell quickly, but scams abound on Craigslist and Facebook.
Best wishes in your search!