Personally, after having a big dog (85#) at one time and traveling all over myself; while traveling they need some space to stretch, walk-around a snig (at least), and room to not have to lay on top of each other.
A RAV-4, Forester, etc vehicles of that size are NOT going to cut it - this gentleman mention 2-3 BIG dogs, not medium sized.
Personally, get yourself either a 2500HD Chevy/GMC OR Dodge 3/4 quad-cab Diesel (not gas) and throw a pick-up bed shell on there for the doggies.
If these dogs are going to be doing a lot of traveling, within the bed/camper shell I would personally lay down some padding with a layer of carpet over it and get each dog a fluffy bed - TRUST me, if you make them comfortable they will travel greatly.
And/or, inside the camper shell, you could have each dog inside their own dog kennel with that same fluffy bed. Don't normally mention this for BIG dogs, as I was never able to find a dog kennel that fit my big dog comfortably - she had LONG legs.
I would NOT choose to place any dog in an open bed, even if they are in dog-kennel - how would you like to ride in the open for hours on end, in all kinds of weather.