Hi: I have a 1997 40th Anniversary Edition Landcruiser with the stock roof racks. I am planning a beach trip (6 hours highway) and will have a large bike rack on trailer hitch. In order to take our dog, I will need to be able to fit a lot of cargo up top. Will the standard rack hold any substantial amount of cargo (coolers, suit cases, etc) or do I need something else, and if I need something else, can someone recommend what I could get. Thanks!