Mt. Aso

Can someone please confirm that this is the current timetable for the bus from Aso station to the Mt. Aso cable car?
Buses from Aso station to the crater: 8:57, 9:52, 10:40, 12:20, 13:25, 14:15 and 15:20

Buses from the crater to Aso station: 9:50, 10:50, 12:10, 13:20, 14:10, 15:45 and 17:00

If so, how much time so people generally spend at the top of Mt. Aso? I'm asking because from what I can tell the bus times don't match very well, so It I take the 1:25 bus from Aso station by the time I get to the crater it would be around 2:15 or something, then the next bus isn't until 3:45. Is there another way to get back to Aso station or does visiting the crater actually take that long?

Thanks!

Yes, these still seem to be the departure times. The one way trip takes 40 minutes in direction of the crater and 30 minutes downwards.

From the bus stop, you will have to ride a gondola, for which I would calculate about 15 minutes one way (incl. eventual waiting time). How The typical person probably spends about 10 minutes around the crater itself. If gases are strong, you don't want to stay longer. If they are really strong, you are not even allowed to go to the crater.

A nice thing to do on a good weather day is to walk a litle bit around the mountain. For example, you could walk down to the Kusasenri-ga-hama plain and rest a little or see the mildly interesting volcano museum, and then catch the bus from there:
http://www.japan-guide.com/e/e4552.html

Thanks Uji. Are the trains from Hakata to Aso (via Kumamoto) JR trains? I'm specifically looking at catching the Limited Express Relay Tsubame from Hakata to Kumamoto and the Limited Express Kyushu Odan Express from Kumamoto to Aso station.

Where do you catch the bus from Aso station to Mt. Aso, just outside the station? Do you buy tickets on the bus?

The trains you mention are JR owned and no problem with the JR pass.

When you get to Aso, I would go to the tourist info booth to the left of the station exit first (it's in a separate building at the end of the street) and get a map of the area and a bus timetable. This gets you a good idea of some paths you can wander around the crater if you have an hour or so to blow. If you can, I'd recommend the path heading for Suna Senri. It's a paved (wooden planks) path running through the black sand, and you can get some eerie moon landscape views of the volcano. Further up this path is a hike up the crater to the highest peak, which is quite a bit harder and will take you an extra hour and half probably.

I'd skip the ropeway and just walk up to the crater (along the paved road) from the bus stop (15 minutes); it'll save you some money and let you get some fresh air.

As for the bus to Aso, it stops right outside the JR station exit--it's a smaller bus so don't confuse it with the large coaches that are highway buses to Fukuoka, etc. Also, note that the Aso Volcanic Museum is not the stop for the crater; just stay on until the last stop. Like all local buses in Japan, you enter and take a ticket with a number on it. When you get off, a signboard above the driver will tell you how much the fare is depending on the number of your ticket. Then you hand in the ticket pay the fare.

And you probably know already, but there're two slots in the money collection machine. One is for breaking coins and bills into smaller denominations; the other (a clear plastic case) is the actual money collection box. My first week in Japan, I actually mistook the two and ran off from a bus thinking I paid, but actually had just exchanged my money instead...how embarrassing.

Thanks for that info, it was really helpful.