Look at pop ups,, they are about the safest thing you can tow that would be comfortable for 5 people. Anything bigger than a 19' trailer will put you way over your max,, Gotta look at the sticker on your door for Maximum Payload, Just the five people will put you close. Planning a long trip will mean coolers, food,drink,camping gear. We had a PUP with our half ton 4x4 super crew and could safely haul our three kids with a friend or two plus dog, coolers,camp equipment and games and firewood. Ours slept 8, it was cozy but worked..
Most 20' and smaller TT's only sleep four maybe, but a well equipped PUP with a deck for storage or bikes might the ticket for a half ton..
Good luck and enjoy!!