If you're gonna have to lift and carry it, you need to know that water and waste weigh 8.333 lbs/gallon. Even a 5 gal portapotty tank weighs almost 50 lbs full. I dunno what size you ordered, but the smallest Camco tank I could find online is 21 gallons, so even if only half full it would weigh at least 100 lbs including the weight of the tank.
Methinks that you'd only have to go through what it would take to use the Camco tank once to convince you that having to put on foulies to go the pumpout, or maybe go when the weather isn't sour even if the tank isn't full yet, isn't such a bad idea after all. Or maybe put a 2-3 gal portapotty aboard to use in an "emergency" till you can get to the pumpout. Its tank weighs only about 30 lbs, which you could carry to the marina bathroom to empty it into a toilet.
--Peggie