Lake Koshkonong is 10,000 acres of shallow water, and from the grass at a lakeside site you can watch ski boats idle back toward the ramps while pontoons drift in to shore. The lake opens up east of Janesville along State Road 59, and the resorts around Milton sit close enough to the shore that a family can level the motorhome on Saturday and leave it there until the next weekend. The days in between belong to the water, with swimming, tubing and a slow pontoon lap of the lake, then supper back at the site under the awning.
Lakeland, the Thousand Trails park, has a mile of frontage on Lake Koshkonong and its own boat ramp, so whatever you brought to float goes in at the campground instead of a public launch. It suits the family that wants the shoreline a short walk from the site and the kids within shouting distance of the water.
Also on State Road 59, the Milton KOA ran as Hidden Valley RV Resort before it took the KOA name, under the same operator family. It's the resort for running the air hard through a sticky August afternoon, with 50-amp service and a dump station for guests on sites without full hookups, so a site without sewer still works for a full week. Pettit's Lakeview Campground rounds out the lakeside choices.
Summer weekends and holiday weeks at the Milton resorts go early, so lock in the site before you book the rig. The pad you land decides how long a motorhome makes sense, and matching a rig to a confirmed site is far easier than hunting for a site that takes the one you already reserved. A couple traveling on their own may find a campervan in Wisconsin slips into a lakeside site more easily.
Rock Aqua Jays ski nights at Traxler Park
On summer evenings the bleachers along the Rock River at Traxler Park fill for the Rock Aqua Jays, who build human pyramids on skis and send barefooters skimming past the stadium bank. The team calls itself the most decorated water ski show team in history, and the crowd is a mix of Janesville regulars and families in from the lake. Shows run Wednesday and Sunday evenings at 7, Memorial Day weekend through Labor Day, with free admission and parking at Bank First Stadium, as of October 2026.
It's an easy night out from the Koshkonong resorts, and you're back at the site before the kids fade. On a day when the lake is too choppy for the boat, Rotary Botanical Gardens in town lays out 26 garden styles across 20 acres, the Cottage Garden Gallery included.
Clear Lake and Blackhawk Camping Resort
On the south side of Milton, Blackhawk Camping Resort spreads through woods between three lakes, with Clear Lake at its edge. It's a second lake week in the same ring around Milton, shadier than the open Koshkonong shore, and the paved pull-throughs mean nobody has to back a long motorhome between the trees.
The value pull-throughs carry 30/50-amp electric, and the premium and elite tiers add sewer, which is the difference between a mid-week trip to empty the tanks and staying put the whole week. For a change of water, Lake Kegonsa up toward Madison is written up as a Madison campervan trip, and Rock Cut State Park, just over the Illinois line outside Rockford, has its own Rockford RV page.