Boy is this a loaded question....My wife and myself are generally the only ones sleeping in our trailer so we bought a 19Ft Ragen that we found used. This was a great find as the previous owner never used it , still had the paper packing on the toilet seat. It came with an onboard fuel system, as well as the other amenities. Keep in mind that the ramp on most Toyhaulers will become an outside deck adding about 8' more living space. Even though it is only 19' if we do need to sleep 4 more we can. This trailer came with a tandem axel and tows great behind my Tundra, and by buying it the way I did I saved about $3500.00US. With that said the size and type has to be something that fits your needs, desires, and pocket book. Just get everything you want the first time no reason to buy less and be unhappy. I did take my 500 over to where the trailer was and loaded it to make sure that it fit before I bought it.