I was went to 龍貓博物館 (又名三鷹博物館) in the end of May, I was purchased the tickets in the sole agent. I learned from the staff of travel agent that people can also buy ticket in Japan's Lawson, however you need to buy the ticket two weeks in advance and it has limited number of ticket to sell.
When I bought the ticket, I also need to bring my passport because they will write down you name in the receipt. If you buy the ticket in HK, you can go the 博物館 anytime. Otherwise, the ticket which purchase in Japan has time frame, I remember is 10:00 a.m, 12:00 noon, 2:00 p.m. and 4:00 p.m.,
Did you get the web site of the 博物館? If not, please let me know, I can send to you.
Maybe my message misleading you. What I want to say is:
(1) In Japan, you can buy the ticket in Lawson.
(2) You need to buy the ticket two weeks in advance.
(3) The ticket which purchase in Japan have time frame.
As I mentioned in my pervious message, the above information which I know was "learned from the staff of travel agent" and you can find the same in the Ghibli Museum's website.
If you access the website, you can find the contact number of travel agent in HK(which is Satexxxxe Travel, I was bought the ticket from this travel agent). Furthermore, when I went to the Ghibli Museum, I was enter the Museum around 3:50 p.m., I found the Japanese people need to queue up to wait for enter, and the staff of the museum let the Japanese people to enter at 4:00 p.m., it was the experience that I encounter.
For the ticket which buy in JTB, I have no knowledge on that. Maybe it is different from place to place. Anyway, thank you for let us know we can also buy the ticket in JTB.
第一日(星期四):
香港-池袋-sunshine city shopping
一定要去'MK KLEIN'買T-SHIRT,香港買$180,日本840日元,布手袋70%約300日元,我BUY 了2個'ALTA'入面SHOP都VERY CHEAP.
第二日(星期五):
Disneyland
夜晚可以在SWEETHEART CAFE坐出面意粉,可以邊食邊睇煙花,多利用FASTPASS可以玩多好多,我合共玩了18個GAME,要去抽飛睇'巴斯光年'SHOW,I AM SO LUCKY 抽到飛坐13行睇SHOW,包你嘩正!
想睇巡遊,最佳位置在'小飛象與幽靈公館後面之間,因這是起點,可以很快看完,玩其他