It depends!
Knew I was gonna get to use that some time today.
I have 2-going-on-3 dogs, which I can transport quite easily in my old beater with cap. Secure three crates in the truck, and I'm good to go.
If you think you are only going to ever have, at MOST 3 dogs, then less is more. Especially as, I predict, gasoline will top $3 per gallon this year, maybe even before summer gets well underway. For a small handful of dogs, a big truck and chasis mount is just overkill. A smaller truck with a 2 or 3 dog box in the bed will work fine.
Lisa