Arrive in the small town of Nakakaruizawa in the morning and head to the Karuizawa Wild Bird Sanctuary. Here you can enjoy spotting not only rare birds in the wild, but possibly also mammals like the Japanese giant flying squirrel, the Asian black bear, and the wild boar. Have lunch in the Old Karuizawa Ginza Street area, then travel to Onioshidashi Park.

At Onioshidashi Park, explore a landscape of volcanic rocks formed by the eruption of Mount Asama in 1783. Nearly 500 people in a nearby village perished in this catastrophe. Today the park is a site of unsettling beauty that still serves as a reminder of nature's lethal power. Around mid-afternoon, drive to Manza Nature Center and get to know more about the geological features, native plants and animals, and local weather conditions of Joshin'etsukogen National Park. Travel onward to Manza Onsen for your first night's hotel stay. Get a good night's rest in preparation for the next two days of vigorous activity.

Start your day with a trip to Kusatsu Onsen Netsunoyu, a top hot springs site with the largest volume of flowing water among all the onsen in Japan. You can observe the age-old practice of yumomi, a manual means to cool down the water's temperature without diluting it.

Next, head to Shiga Kogen Nature Production Center for a guided 10-kilometer trekaround the ponds of the area. You'll take a ski lift up to the peak of Mount Maeyama for splendid views, then marvel at the floating islands within Shibuike Pond. The hike will introduce you to all manner of alpine flora and other amazing scenery that forms the core of Shiga Highland, including the marshland of Shijiuhachiike and Onumaike Pond's stunning cobalt coloration.

Once the guided trek wraps up, check into your accommodation in Shiga Highland for your second night's stay. There are a variety of hot spring areas to choose from such as Kumanoyu, Hotaru Onsen, and Hoppo Onsen, each with a range of inns and hotels to suit your needs.

In the morning, experience spectacular views of Shiga Highland from above with the Shiga Kogen Golden Line. This is a series of three gondola lifts (Shiga Kogen Resort Gondola, Bunadaira Gondola, and Higashitateyama Gondola) that takes you from Shiga Kogen Resort to the summit of Mount Higashitateyama in about 30 minutes. Take in seasonal views of alpine blooms and verdant mountainsides, and enjoy a hike at the summit or simply sit and relax on a garden terrace 2,000 meters above sea level.

Afterwards, take a bus to Jigokudani Yaen Koen, also known as Snow Monkey Park. You'll be delighted to observe the Japanese macaques (or snow monkeys) bathing in the hot springs, a memorable and picturesque experience that will stay with you long after your trip is over. When you've had your fill of the snow monkeys, take the express train from Yudanaka to Nagano in around 45 minutes and wrap up your excursion at your own leisure.