How to go to Takachiho Gorge from Aso

I will be staying in Aso Farmland this Feb 13th. Can anyone help to advise how to get to Takachiho Gorge from Aso area or from any train station near Mt Aso? Can I complete the vist of Mt Aso & Takachiho Gorge in one day? I will check out from Aso Farmland and 14th Feb & plan to visit Mt Aso & Takachiho Gorge, I will return back to stay in a pension near Tateno station for the nght. Is there any locker for luggage iin any station? Or is there car rental for 1 day from Aso station? Thank you.

I will be staying in Aso Farmland this Feb 13th. Can anyone help to advise how to get to Takachiho Gorge from Aso area or from any train station near Mt Aso?

There is a bus that connects the areas. It takes about an hour and costs 1280 yen one way. More details are on this page:

http://www.japan-guide.com/e/e8051.html?aFROM=4552_8050

Can I complete the visいt of Mt Aso & Takachiho Gorge in one day? I will check out from Aso Farmland and 14th Feb & plan to visit Mt Aso & Takachiho Gorge, I will return back to stay in a pension near Tateno station for the nght.

Its possible, but would be rushed if doing it by public transportation. There is only one viable bus per day leaves Aso at 11. That gives you little time for Aso, and little time for Takachiho. A rental car will help speed your travel.

Or is there car rental for 1 day from Aso station?

Yes there are a few. Here's one:

http://www.ekirenkyushu.co.jp/

You won't necessarily need a whole day for Takachiho, but I recommend spending a whole day there and staying overnight so you can enjoy the kagura dance: http://zoomingjapan.com/travel/takachiho-miyazaki-kyushu/

It's impossible to do Mt. Aso and Takachiho in one day! I've been to both and getting to Mt. Aso can take a long time especially if the weather is not so good. The volcano was a bit too active when I visited, so we had to wait for a few hours to see if it would calm down and then go up there. Even if that doesn't happen, it's impossible to finish sightseeing for both places in ONE day!

It is possible to do just the crater and the gorge in a single day, especially if you start and end in Aso. But yes, trying to doing everything in both areas probably won't be possible even with a rental car.