My trailer frame is 17 feet  x 4 feet  And of course the wheels and fenders stick out much farther. I think you could make this work. There are a few things to think about .  Haveing a slightly shorter  trailer helps in launching . You can launch in very shallow water . I have launched mine in my yard.  Having a long trailer could  give you more tounge weight since there will be less boat hanging over the rear side of the wheels.  You will want to make sure you have center wheels , Most of the boats weight should  be carried on the center wheels . My boat also has carpeted bunkers the bunkers well help keep your boat level and help to carry some of the weight. My boat also has two guied rollers on the back ,helps keep boat centered to the trailer for loading and launching.  I think yo could use rollers instead of bunkers, but if you do use several sets to help carry some of the hulls weight.  I am no expert but hope this helps.     In the parking lot I use a two step ladder to enter and exit boat during setup.