How much gear (size and weight) are you talking about, in general? What gear is it?
Before my 4Runner I had a full size pickup. On a week long trip my wife and I would fill the entire truck bed with gear. It was uncovered in Rubbermade Action Packers but organized.
I liked the 4Runner right off the bat because our gear was safe and secure in a covered space. Since having kids the space has decreased and the amount of stuff has increased.
I have a roof rack, hitch basket as well as a 4X8 trailer. Storage space differs greatly between those options. If I maxed out my roof space that amount of gear would fill maybe a sixth of the trailer space. If it was just that gear I'd throw it on the roof rather than pull a trailer. I will say my mileage drops with stuff on the roof.
Trailers have their draw backs for us where we go. I wouldn't wheel with one. You'd be stuck at 55mph and some campsites consider it a vehicle and you have to keep it on the parking pad and not off the road.
I'd suggest you get a hitch basket, pare down your gear and pack like a boy scout. I can pack the family for a week camping with the rear cargo area and the hitch basket. I tend to only use the roof rack for smaller things as the gas mileage drops, that stuff gets whacked on trees and if it rains it gets wetter than stuff off the back.
This is a weekend trip with more gear than we need. My float tube took up a lot of interior room. Actions packers are larger than I want on the roof. If they are heavy they are hard to load, plus they are tall.
Enough crap to warrant the basket but not a trailer. I can pack that extra stuff on the basket easier than on the roof.
This was quite a load. The return trip home had nothing on the roof as we burned the wood and ate all the food. I noticed a 3 mpg drop on the trip going up the hill. The EZ Up fit perfectly on the rack. It's heavy to lift to the roof and slides around. It also doesn't fit inside with car seats.
My trailer gets used for house stuff and spends most of it's time on the paved trailer pad on the side of the house.