I pickup up my 4300 lb dry weight camper with flatbed and no ties.
But the camper had strong jacks and no problem to mount hooks on flatbed, so I used lot of nylon straps to hold it against the headache bar.
That said after about 200 miles the camper shifted on steel deck and I had to reposition it, putting the straps in X-patter now and that made 2000 miles trip home with no future problems.
For longer bed you will need to figure out solid front stops.
GET RUBBER MAT if you have steel bed.
Lot of strong ties in all possible directions.
Straps are cheap, picking up dropped camper from the middle of highway is not.