I survived one week in Japan with only RM1.5K, but I could manage only because my accommodation was free. Food and transportation in Japan is expensive so make sure you plan your budget properly.

Follow the time table. From Nagoya to Takayama earliest bus was 7.30am at Meitetsu Station bus station or 7.40am at Nagoya Station.
You will arrive Takayama at noon.
From Takayama transfer to Kanazawa line. You will reach Kanazawa at Night.

You still need reserve the seat.  First buy pass. Then go Nohi bus web buy bus ticket.  When buy bus ticket key in pass number.

Why take Bus?  Slow and Expensive.

At Nagoya Station to Kanazawa just take Train. 

JR Limited Express "Shirasagi"
7200Yen & 3 Hour Journey only

if got shirakawa go then worth it.

I plan to change some of my money into Yen at Bank Negara Malaysia, but as far as I know the smallest denomination possible is merely 1000 yen. Is there any way to exchange 500 and 100 Yen coins locally? If not, is there any option in Japan?