There are a whole lot of parts in The Cottage Grove area where you can find many things to do outdoors. There are over 1100 acres of parks in this area so you will not have any problem finding one that suits your needs. The Ravine Regional Park is probably the biggest and most visited Park in town. There are so many great Trails here that you could spend all day walking around and not even see half of them. If you want a fun place to go then this would be our main recommendation.
The Row River Trail has some great hiking and biking trails with plenty of spots to smoke along the way. There is a bridge that goes over a little creek and some nice views in the area around there. Plenty of privacy for sure. Cottage Grove also has a Historic District downtown that is fun to walk around and have a trip down memory lane. Schwarz Park is also a nice little camp ground and nature area you could putz around and smoke where ever there. Saginaw Vineyard is a nice winery if you want to do some wine tasting after you smoke.