Budgeting for an unbudgeted trip

In May, on a whim, I deiced to plan for a trip to Japan.
Without much thinking and consideration of my finances,
I booked the air ticket as there was an offer on Singapore Airlines
for a return trip ticket from Singapore to Tokyo (Haneda).

In this and subsequent posts, I will be putting up my proposed budget for the trip,
hopefully, I don't blow this budget.

This is a budget that I have drawn up after checking out all the websites.
Well, this is my first trip to Japan and i realized that Japan goes by a Honor system.
Most places do not require you to pay via credit cards or transfer the payment to secure your booking. They will hold the room for you and you settle the payment when you arrive.

So I wonder if most Japanese business function on a cash flow accounting system instead of a double-entry system. But that is a story for another day.

ITINERARY
Destination	Days (Stay) Nights		Lodging		J Yen	S$
Tokyo	2	2	Kimi Ryokan Tokyo		7875Y	103
Hokkaido-Biei-Furano	2	2	Cress Guesthouse-Biei		10000Y	131
Sounkyo Onsen+Daisetsusan	1	1	Resort Pension Yamanoue @ Sounkyo		8800Y	115
Hokkaido-Sapporo	2	1	Sapporo City		S$68	68
Mt Fuji-Hakodate	2	1	Mt Fuji		3900Y	51
Tokyo	4	3	Shinjuku Washinton Hotel 3-2-9 Nichi Shinjuku Shinjuku-ku Tokyo Ph:81 33343-3111		$252.20	252.2
					Total	720.2
TRANSPORTATION
From (Source Station)	Mode	Dep	To (Destination)		Jyen	S$
Haneda Airport to Kimi	Limo Bus	Haneda	Ikebukuro West Station		1200	16
Ikebukuro to Kimi	Taxi	Ikebukuro	Kimi		2500	33
Kimi	Limo Bus	Haneda	Haneda-Flight to Sapporo		1200	16
Monorail to Airport	Monorail	Haneda	Haneda-Flight to Sapporo		720	9.5
Air Ticket to Sapporo	Place	Haneda	New Chitose Airport (CTS)		21600	283
New Chitose Airport	Train	Biei	Biei		1040	14
Biei Furano Round Pass	Train	Furano	Furano		5400	71
Sounkyo	Train/Bus	Biei	Sounkyo Onsen/Daisetsusan		1920	25
Sounkyo	Train/Bus	Takikawa	Sapporo		1920	25
Asahikawa	Train	Sapporo	Sapporo		4170	55
Sapporo	Train	New Chitose Airport	Tokyo		1040Y	14
Haneda Airport	Kawaguchi 5th Station	Haneda	Mt Fuji		2400Y	31
Kawaguchi Sta.	Bus/Monorail	Gotemba	Gotemba(Outlet Mall)		1470	19
Gotemba	Bus/Train	Gotemba	Shinjuku		1630	21
Shinjuku	Monorail/Bus	Haneda	Flight back to SG		1200	630
					Total	1263

Total so far including accomodations and transport now amount to close to $2000.

Here's an estimate of the break down of the cost though cost might vary depending on the season you are travelling. I will be travelling in September of this year and hopefully I can stay within a budget of
S$3000.00 including personal expenses and gifts.

I had previously spent only S$1100 for a two week trip to New York and Boston and hope to stay within a budget. The above 2 week trip involves bunking in with a friend for 2 weeks in Boston and staying at a 3-star mid-town hotel in New York City that is within walking distance to the Lexington Subway. However the $1100 includes transport, meals personal expenses only andit excludes air ticket from SG to New York City.

Leave me comments on tips on how to save during my Tokyo and Hokkaido trip.
I will appreciate any tips you can offer and will write up about it when I return after using your tip.
Might also send you a gift if my budget allows.