Best location in Shimabara Peninsula

We are planning on spending 2 nights in the Shimabara Peninsula in late October and there are decent hotels in Unsen Onsen, Obama Onsen and Shimabara Onsen.
We are hoping to explore the coastline, hike on Mount Unzen, enjoy the beauty of the national park and eat like lords, where would be the best location to base ourselves?

I don't think it really matters too much. Everything is within one hour travel.

If you are traveling by public transport, Shimabara might be slightly easier to access due to bus and trains. Bus only for the other two.

But if you are traveling by car, pick whichever you eyes like.

I haven't been to Obama, but it look like just a onsen hotel area. On paper it seems to lack any sights. Unzen has a least the hells and the walkways through them. Shimabara has the castle, the street drains and building with the coy fish, the small castle and sandy beaches.

I'd probably go Shimabara. But with a car and everything being within one hour of travel. Maybe the cheapest???

We'll have a hire car, thanks very much for the info, it's very useful.

Shimabara Peninsula, an other great area to explore and enjoy with a camping car.
Been there, done that. The road up to the parking lot at Mt Unsen, if weather cooperates, has spectacular views. There are a couple of look out points.
The hike is well marked...but some areas are off limit because of volcanic activity.

If you are there during the last week of Oct staying in Unzen would be nice as you can go for a special night event.
http://unzen.org/premium_night/

Thanks!
So the premium night is a bus tour in the evening with great views of the night sky and illuminated autumn colours on the mountainside?

It�fs a bus + ropeway package tour for night sky and star glazing up the mt. And yes there is a good chance autumn foliage can be enjoyed on the mt slopes in Unzen during late Oct, although early Nov is said to be a better time.

http://weathernews.jp/s/koyo/spot/28401/