How to rent a car in Japan

Herz

Nippon Rent-a-car

There is no AVIS in Japan.
Nippon Rent-a-car is biggest rent a car company, I think.
You will be able to find Nippon Rent-a-car in Big cities.

When you arrive Narita Airport, you have to go to ground floor if you want to rent a car.
You can find Nippon Rent-a-car(English Page), Toyota Rentacar(Japanese Only), Nissan Rentacar(Japanese Only) and Orix Rent-a-car(Japanese Only).

The public transportation facility is recommended to be used when not accustoming because Japan is "Keep to the right". :-D

What you need to know Living in Japan, etc.

living in japan from gotjapan.com

It overflows with useful information.

Which is best way to go to MakuhariMesse(Tokyo Motor Show, etc.)

KeiseiBus is best, I think. WebPage is here (Japanese Only).
When go out Customs exit, you can find bus counter and buy ticket.

If you have any interest to use Trains, use JR(Japan Railways) or KeiseiLine from B1 Floor. I can not recommend to go to Makuhari Messe. Of cource you can go easily to Tokyo Sta.

Another choice, to hire pick up and transport services.
There are some company. you can google, please try.:-P
Limousine hire Co.,Ltd
Tokyoairporter.com

Please see here(from Wikitravel) about details.

Indoor Skiing

Sayama Ski & Snowboard(in Japanese)

If you want to ski, here is one of choice. No rain, No Blizzard。:-)
Also you can know Japanese Technology, I think.:-P

Hitchhiking in Japan

Hitchhiking in Japan from WikiTravel

You are almost safe in all places in Japan.
But, please hitchhike at your own risk. :-P