I did a unique way of mounting the Baxleys down in my Toy Hauler, since I didn't want to go through the floor either. I bought a piece of 3/4" plywood and cut it to the full width of the inside of the garage area. The "length", from front to back was enough to set the Baxleys on and have a little bit more. At that particular location in my trailer, there are three floor anchors already in the trailer from the factory. So, I removed the trim plates from all three of them and cut out three circles in the plywood so that those holes would be exactly over the existing factory tie down points. Once those holes were made, I set the Baxleys in the exact location that I needed them to be and drilled the plywood, but not the trailer floor. I flipped the plywood over and put carriage bolts in from the bottom of the plywood and countersunk them flush. I then flipped the plywood back over and the bolts were now sticking up through the plywood like studs. I then placed the plywood back in position so that my circles were exactly over the floor tie downs and I reinstalled the tie down trim plates on the plywood instead of on the trailer floor. I had to use screws that were 3/4" longer, but they went right back into the same holes that were already in the floor from the factory. So now, if I need or want to take the Baxleys out of the trailer, I simply loosen the nuts and take them off of the studs sticking up through the plywood. Of course I needed a way to keep from walking on or stubbing my foot on the studs sticking up, so I cut a piece of 2"x4" and drilled it to fit over the studs....one for each set of bolts. The plywood was painted to match the color of the rubber flooring in the trailer, and I even put 3/4" x 3/4" aluminum angle on the edged of the plywood to give it a more finished look....and to keep it from splintering on the edges. Here is a pic of the finished job....
https://imgur.com/qyRmYC9
https://imgur.com/vQteEzh