Warriorgus,
That is a tough one. Since most of the land along the Mississippi is owned by the federal government and they discourage any development, there aren’t many resorts or campgrounds along the river. I do know of a couple in Wabasha.
This one is owned by the city and I know they rent to campers on a yearly basis.
Mississippi Parkside Marina
829 3 St W WABASHA MN 55981-1117 (651) 565-3809
This one is privately owned (I think) and they at least used to rent, but I don’t know anyone in this one at this time:
Wabasha Marina Boatyard
1009 Main St E WABASHA MN 55981-1468 (651) 565-4747
Both of these are about 5 miles south of Pepin.
I don’t know much about these two in Lake City, but they are right on Pepin:
PLOTE ACRES CAMPGROUND
RR 1 BOX 174 LAKE CITY MN 55041-9383 (651) 345-3056
LAKE PEPIN CAMPGROUNDS & TRLR
1818 N HIGH ST LAKE CITY MN 55041-9048 (651) 345-2909
These are at least a place to start.
Pete