Short bed camper on long bed truck - Tips for frontal brace?

I would slide the camper all the way forward in the bed of your truck. Secure it with tie downs that bolt to your frame. Leave the tailgate on. Then you can access everything behind the camper.

With a load, you may stop fast enough to make the TC want to slide forward, but the rubber bumpers will be against the pickup box. You cannot start fast enough to make it go to the rear.