This time I drove, but I think it’s easily walkable from Toshogu shrine area (should be about 20 min. walk). There’s also a bus stop nearby, but if you’re visiting in high season and want to continue afterwards to Lake Chuzenji, you’re risking not being able to get on that same bus again (it will be packed with people, especially on a weekend). So, I’d recommend to either have your own wheels or make it just a downtown Nikko trip, without going up the Irohazaka road to the mountains. There’s plenty of things to see and do around Tamozawa Villa, you’d be occupied for a day.