mstell2, do a "bike rack" search on the forum. Hauling bikes on the rear of a trailer has been discussed many times here. Taking weight off of the tongue, bike movement, rack or weld failure, are among many things gone over. The consensus is that there are better places to carry bikes.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263