I'm in a very similar situation (married with a young child, mostly around-town mileage, daily driver VX) and I think you'll be fine as long as you (1) maintain another primary family vehicle, (2) do some reasonable upgrades to the VX to address its shortcomings. Here's a quick list of to-do's that I think would solve/minimize the main issues in this thread:

- Rear Sear Access - Get with tom4bren on a passenger side seat extender, which dramatically improves the accessibility of the rear seat (although it will always be difficult for a full-size adult). IMHO this is a MUST HAVE if you plan on keeping the backseat in the VX. Taking a car seat in/out of the back is do-able but a pain, so you might want to consider buying an extra set of seats to leave in there. We only take my daughter in the VX when the family vehicle is in the shop, so I just put up with the once-every-three-month hassle.

- Driver rear visibility - Buy a seat of $3 blind spot mirrors, a $15 fish-eye lens for the back window, and some Amigo/Rodeo center-less headrests for the backseats from your local junkyard and you're in business for cheap. I only have the blind spot mirrors, and they're sufficient for most visibility needs. Buying a backup camera is a nice-to-have, but certainly not necessary IMO.

- Poor backseat visibility - Dramamine and air sickness bags maybe? My wife got nauseas (sp?) from the tunnel vision effect of riding back there the other day.

Other upgrades to consider: rear seat cupholder for the kids' drinks (can be pulled from an old Trooper or ordered online), step bars to ease access for little people, SBC brackets to correct the window problem.

Bottom line is you can probably spend < $200 to make the VX liveable as an occasional family truckster.