day trip from Kumamoto to Aso san

is it possible to do a day trip to see Aso San volcano caldera from Kumamoto and how?

what is the time table JR from Kumamoto to Aso staton please?

If a day trip is not possible,will the nearby town Miyaji a good place for stay if I am heading to Beppu the next day?

thanks

is it possible to do a day trip to see Aso San volcano caldera from Kumamoto and how?

Yes. The recommended way would be by rental car:
http://www.japan-guide.com/e/e2024.html

Otherwise, there is a direct bus from Kumamoto to the crater of Asosan.

Still otherwise, you could take a train to Aso Station and then a bus to the crater.

It is explained here:
http://www.japan-guide.com/e/e4552.html

what is the time table JR from Kumamoto to Aso staton please?

Here you go:
http://grace.hyperdia.com/cgi-english/hyperWeb.cgi

Aso is located between Kumamoto and Beppu. In any case, it would be a waste to return to Kumamoto just to travel via Aso to Beppu again on the next day.

Note that the bus from Kumamoto to the crater of Mount Aso continues from there to Beppu. It also stops in Kurokawa Onsen just outside the caldera of Aso. Kurokawa is one of the most pleasant onsen towns in Japan and would be a nice place to spend a night.

Take the Kyushu Odan Bus running across Kyushu from Kumamoto to Beppu. I took it last month and was very convenient.

Kumamoto Transport Center 10:10--12:06 Mt Aso West (Take the Ropeway to the Crater) 13:36--17:06 Beppu Station

This service also stops at Kurokawa Onsen and Yufuin. A two-hour day bath use is also possible. The next bus will show up in two hours.

You might consider purchasing a 3-day Sunq Pass for 8,000 yen (or 6,000 yen if a voucher is purcahsed at Osaka Umeda Hankyu Bus Terminal, under Hankyu Umeda Station, or Tokyo Shinjuku Keio Bus Terminal.)

How to get to Keio Bus Terminal from JR Shinjuku Station:
http://gutereise09.blogspot.com/2008/08/navigation-from-jr-s...