Johnnie
No worries on any give or flex on the floor mat, it's only about 1/8 inch thick and very dense. I did remove the aluminum wall trim that was way down on the floor and tried to cut the rubber mat to fit as tight as I could get it, but after about a week of laying in the trailer in the summer heat it started to bubble up a bit in the center due to expansion, so I removed the floor trim and trimmed about a 1/4 inch off the one side. Then it fit fine and laid perfectly flat. But now in the cold Minnesota winter I can see it has shrunk and pulled about a 1/4 inch away from the wall. I'm glad I did not glue it down at all, because I have come to the realization that it will be a floating floor and it will shrink and expand with the seasons. I'm OK with that.
I did remove the floor trim right in the door way and placed the mat under this trim. I didn't want to trip on it in the doorway.
And as far as my bike tie downs, I have not placed them yet.
Once I finish the entire build, I'll go to a truck scale and weight the trailer loaded with the heaviest bike I have. I'll then calculate my tongue weight and place the bike wheel chock in the exact spot to keep my tongue weight at about 10% of total trailer weight. Then I'll place the tie downs exactly where they need to be. More forward will add tongue weight and further back will lessen tongue weight.
My Road Star weights over 800 pounds and my Dual-sport BMW only weights about 400 pounds, so it will still be a bit of a guessing game.
I have a pretty good idea of where they will be. One will be just inside the door right under my power converter, one may actually be inside the bathroom. I'll buy the style that will bolt down on top of the rubber mat and be bolted through the floor with about a 5x5 inch metal backer plate underneath the 3/4 inch plywood floor. Or if I'm lucky enough to land on top of a frame rail, I can bolt straight through that.
Gadget Man