^^^^What JRTJH said is excellent advice. Also, if you pick an area, you can check reviews on the campground on line. Many will tell you if it is a tight fit, tight roads, etc on the reviews. Google is good, RVParky.com is good, there are several others. I just planned an entire 2 week trip to the Wisconsin Dells, the Upper Peninsula, Traverse City and Holland, MI all on line. I was able to check the hook ups, check the spots, verify that I will have enough room, etc, all on line. I even used the satellite images to verify that what I was reading was accurate. It all helps. 40 foot is long, but not impossible. Keep in mind that when you are booking, the length selected is for the trailer only, unless it says to include the tow vehicle in the number. I hope that this helps.
