Without knowing more about the size of your family, for most folks, IMHO, there are two popular rigs:
1. Heavy duty 3/4 or 1 ton truck and a suitable fifth wheel trailer. Fifth wheel has a lot of advantages over travel trailer.
2. Motorhome with towable vehicle. Diesel works better for most due to larger size, higher cargo capacity, ride quality, etc.
But...as already stated, there are folks out there on the road full time that are happy with travel trailers of all sizes, class C or even B motorhomes, and even a few with smaller rigs such as a conversion van, pop-up or other.