My advice - get a smaller tank and dump more frequently. Unless you or your husband is built like Arnold Swarzenegger, those things get heavy really quickly. Yeah you can pull them with your truck, but first you need to get them hooked up after you've filled them.
Why am I an expert? I CG hosted for the NPS last summer in a campground with a dump station, but not sewer at the host site. I used one all summer. Even though my combined grey and black tanks were 80 gallons, my portable tank is 22. That was still tough sometimes to drag down the side of the trailer to the truck and bounce over the campground roads on those tiny wheels.
If you've got to lift it into the bed of your truck to transport to a dump, forget it! 20 gallons of waste will weigh 160+ pounds.
