If the 4002 floor plan is what suits you best go for it. I'll bet Newmar has the same or similar floor pan in other models, though, and chances are other manufacturers have something close. The 4002 layout doesn't appear to be all that unique, but perhaps you have already studied other offerings. Note: I just checked and the 4002 is available in the regular Ventana and the Dutchstar as well. Either of those models would be more capable (and a bit more expensive too). Don't be afraid to go a few years older to meet your budget constraints.
As ferfer says, some of the previous years Ventana LE's had a relatively low CCC (Cargo Carrying Capacity), so check that out. I'd be looking for something north of 3000 lbs, preferably 4000+. Some earlier ones had the Allison 2400 transmission instead of the 3000 as well. The 2400 is adequate, but the 3000 is superior.