Susie is from the Taylors Falls, MN and St. Croix Falls, WI area. Last weekend we camped and celebrated our 34th anniversary where we honeymooned in the Wisconsin side Interstate State Park at St. Croix Falls. This is an amazing area with beautiful and dramatic walks to the bluffs overlooking
the St. Croix River. It's not far from Rice Lake in terms of a travel objective for the day. I'd avoid St. Paul's rush hour and could help you with route info, poison ivy spottings (dogs y'know...), and the trail to the bluff -- safe, good guard rails, etc. They have showers and a limited number of electric hookups in the north loop and you'd generally find those available weekdays only this time of year. They have a website - WDNR - Find a State Park or Forest
The Minnesota side Interstate park is a distant second IMO -- too cramped. Chequamegon Nat'l Forest
has some nice areas but is all boondocking of course.