It is my favorite time of year for hiking in Vermont and like a faithful old friend Mount Mansfield still offers her challenging beauty by way of the Long Trail. You will find her trail heads just past the start of the Notch road. To your left you'll find the trail head. It is about 2.5 miles to the top with some very challenging scrambling at the end. For a less strenuous climb you can also end your hike at Tafts Cabin. A great place to relax and have lunch as well. If you're really looking to prove yourself try the Hellbrook trail, and good luck!
For a less challenging day hike follow the Smuggler's Notch Road to the top and park in the parking area. Across the road you will find the trail head for the Sterling Pond hike. It is 1.1 miles up to the pond. It is a short hike and fairly steep, but a good one for most intermediate hikers and kids. Don't forget to take some time to discover the caves at the parking area, it will prove to be a memorable day for everyone.
Two other short day hikes worth checking out are the Pinnacle trail and Mt. Elmore. The Pinnacle can be found just out of town off Stowe Hollow Road. It is 3.2 miles of moderate hiking that ends with stunning views of the valley and Mount Mansfield. You can find directions here: http://www.trails.com/tcatalog_trail.aspx?trailid=HGN202-047
Elmore Mountain Trail is located in Elmore VT, in the state park. It will cost 3$ per person for entry, but the beauty of this hike during peak foliage is well worth the fee. Hike 1.25 miles to the Fire Tower and I dare you to make it past the first flight of stairs! You will be rewarded with beautiful views from vistas along the trail. Hike and additional half mile to Balance Rock and you've earned your lunch at the Bees Knees in Morrisville. Here are directions to Elmore State Park: http://www.trails.com/tcatalog_trail.aspx?trailid=XTM006-019