I'll toss in my two cents worth of Info as a South-Lander: As for Camping near the Mall of America, my daughter lived in Eagan, MN for 2 years some years ago. A neat county campground near Eagan was Lebanon Hills Campground
12100 Johnny Cake Ridge Road in Apple Valley MN. It would not be to far to drive to the Mall from there. Apple Valley is about 20 miles south of the Twin Cities and just 10 minutes south of the Mall of America (at least that is what the zoo web site has listed). Not sure of a closer one. It is close to the neat MN Zoo
Directions to Zoo
Lebanon Hills Visitor Center
IMHO it would be more fun going to the zoo than visiting the other zoo. Ha! But is worth seeing, it is large with a small amusement park inside, in the center section. Perhaps even larger than when we there last, about 6 years ago, maybe today or at least close. I enjoyed seeing the place. Even did some shopping, MN does not charge a sales tax on clothing & shoes, which can save some cash. A nice place to do some serious walking for sure. But it was a zoo the last time we were there. I believe it was on a Labor Day Monday. Not the best planning for going, but it was a side trip.
Speaking of zoos, in St. Paul there is a really nice small ZOO
. Located in Como Park.
But Lebanon Hills Campground would be the place I would choose to visit the Twin Cities
However, not sure if the fees are good or not for you:
Non-refundable reservation fee per site per reservation: $7
Full hook-up—water/electric/sewer (site/night): $30 + tax
Electric only (site/night): $25 + tax
No-hook up tent site (site/night): $17 + tax
Firewood (bundle): $7.00 + tax
Dump Station (non-guests only): $8