Hello Aldin,
> I would like to combine with a visit to Hyakuri on 6 & 7 Sep.
Photography, numbers or just watching?
If you are limited to public transport, there are buses to and from Tokyo Railway Station to the terminal at Ibaraki International Airport on the western side of the base:
http://www.ibaraki-airport.net/en/access/bus.html
The timetable has improved somewhat recently:
http://www.ibaraki-airport.net/en/access/bus/tokyo.html
As flying tends to start around 08:00, they are a viable option, if you don't mind a long journey back into the city.
The alternative I have used in the past is the bus from Ishioka Railway station to the terminal.
http://www.ibaraki-airport.net/en/acces ... hioka.html
For train connections, use Hyperdia:
http://www.hyperdia.com/
There are hotels in Ishioka:
http://www.ishiokaplaza.com/
http://www.hotel-grandmariage.com/
But based on price and an English language website I usually stay three stops down the line in Tsuchiura at the Toyoko Inn next to the railway station:
http://www.toyoko-inn.com/e_hotel/00175/index.html
The terminal should be fine for numbers of flying aircraft, but as the runways are 03/21, you may want to be on the eastern side in the morning for photography, especially if you can find someone who can get you access to the "Peace Gate" area. A taxi from the eastern side of Ishioka Station to the eastern side of the south end of the base should cost under 5,000 yen, but assuming you can't speak Japanese, you will need a map / Google Maps printout with the location you want to go clearly marked, and you will probably have to walk to the terminal as the sun moves round at lunch time (it takes me about an hour).
The airport terminal does have a viewing area on the upper level, but last time I was there I noticed that the glass at the front went opaque when you view towards the military base area, but is transparent as you turn south towards the 03 approach. The area by the door to the viewing deck is raised, so you can see over the glass more easily, but most photographers congregate on the mound to the south of the terminal building next to the two Phantom gate guards.
> Is this a good time to spot F4s
As good a time as any, assuming there isn't a typhoon happening.
http://www.jma.go.jp/en/warn/314_table.html
(Late August to mid October is typhoon season in Japan.
> And is there a possibility to request for an Air Force Base tour?
I believe in the past the base website:
http://www.mod.go.jp/asdf/hyakuri/index.html
https://translate.google.co.uk/translat ... edit-text=
Has had information regarding tours, although that may just have been to look at the preserved aircraft by the north eastern gate, but I can't see anything like that at the moment.
Hope this helps,
Jonathan.