Since 2008, the fuel alone along my RV trips ranged between 65% to 68% of my total vacation cost, as my per day expenditure costs were over $150 per day when the fuel prices skyrocketed however in 2012 and 2013 that figure had lowered down under the $150 per day threshold.
Now be aware, those figures mentioned were compiled while vacationing in Northwestern Canada for every consecutive year from 2008 thru 2013, while only passing thru Interior Alaska enroute to Canada or returning home, so in other words the fuel prices in this region of Northwestern Canada are well higher than the continental US, Southern Canada and Alaska.
In comparison to fuel prices in Southern Canada being relatively cheaper vs Northern Canada prices, that can bear anywhere between a 15% to a 30% variation within Canada alone depending on what routes you take towards Alaska, however you will still need to purchase fuel somewhere within the Northern BC region where fuel will cost the most in order to reach Alaska by driving thru Canada, unless a rig has a large enough fuel capacity capable to travel well over 700 miles before refueling in order to skip a fuel purchase in BC altogether, as making one fuel stop in Alberta (cheapest fuel prices in Western Canada) and one fuel stop in the Yukon enroute to Alaska could generally save 15% to 20% on total fuel cost purchased within Canada (around $300 for my rig if it were ever capable) in comparison to most of us that don't have that capability to make two or less fuel stops in Canada to reach Alaska.
As others have noted : The best way to lower RV costs for those concerned is to increase more days on vacation (less overall cost per day) as you can control spending much less on other categories like restaurants and site fees if one feels the need to.
The price of energy increased significantly since 2004, and since 2008 our RV commuting costs have increased even more big time, in which there is hardly no way to get around the fuel price factor anywhere in North America as we have no control of pricing, but you can hedge a bit by lowering costs on other expenditures if one feels that is an issue.
No matter how fuel efficient a vehicle is versus a typical large RV, sure you can save some fuel costs that way thru Canada to Alaska, but fuel costs is still going to be one of the most expensive expenditures, and driving an RV will be the most expensive expenditure for fuel, period.
It's nice to sometimes be selective on purchasing less fuel at higher priced regions within reach along my chosen route while carrying spare fuel, while keeping comfortable in current fuel supply as dual tanks has its advantages to fill one tank by passing thru one stretch, and fill both tanks when reaching lower priced regions...
I will save roughly $40 to $50 in fuel per Canada trip by selective purchasing in the RV after comparison or around 2% in savings which helps spend it on other things, as in 2008, 2011, 2012, 2013 when filling up in Fort Nelson upon my return home, I dispense my 10 gallons of spare fuel first that I never used upon duration of the trip and immediately save $12 to $19 depending on the fuel prices between Fort Nelson and Fairbanks.
I also learned over the years in Canada when arriving to overnight in a town while having to purchase fuel, purchase it before crashing out as on one occasion the following morning I seen a 10c per litre increase and on another occasion seen another 3c per litre overnight increase....compared to lowering fuel prices which do not drop as gradually.
I have posted my total expenditures for 2012 and 2013 to give a general perspective on how my costs are broken down, as to my surprise how real close percentage wise these categories were.
The majority of admission fees and camping fees shown was due to the Rocky Mountain National Parks of Banff, Jasper, Kootenay, and Yoho, which in comparison to total vacation cost only accounted to roughly 5%, which to me was definitely worth visiting in 2011, 2012, and 2013 (so far).
2013 Expenditures Total : - $3073.93 USD - 23 days at $133.65 per day
Canada Dollars Disbursed : $2677.89 CAD - at $1.000 USD exchange rate
Fuel purchases - $2014.19 USD (65.52%) - 409.2 US gallons at $4.922 per US gal
Canada Dollars Disbursed : $1693.70 CAD - 329.6 US gallons at $5.138 per US gal within Canada
Total miles - 4789.7 (at 11.70 miles per US gallon) .4205 US cents per mile
Non fuel expenditures - $1059.74 USD (34.48%)
Canada Dollars Disbursed : $984.19 CAD at $1.000 USD exchange rate
Combined restaurant and tips - $381.90 (36.03% non fuel) or (12.42% total vacation cost)
Restaurant - $294.66 (27.80% non fuel)
Tips - $87.24 (8.23% non fuel or 29.61% added to restaurant tab)
Gifts or souvenirs - $164.45 (15.52% non fuel) or (5.35% total vacation cost)
Grocery - $159.24 (15.02% non fuel) or (5.18% total vacation cost)
Retail - $122.05 (11.51% non fuel) or (3.97% total vacation cost)
Camping - $102.90 (9.71% non fuel) or (3.35% total vacation cost)
Admission fees - $46.70 (4.40% non fuel) or (1.52% total vacation cost)
Showers - $27.40 (2.58% non fuel) or (0.89% total vacation cost)
Bar tab - $22.50 (2.12% non fuel) or (0.73% total vacation cost)
Automotive - $16.80 (1.58% non fuel) or (0.54% total vacation cost)
Internet usage - $10.00 (0.94% non fuel) or (0.33% total vacation cost)
Beverages - $3.80 (0.35% non fuel) or (0.12% total vacation cost)
Short changed - $2.00 (0.19% non fuel) or (0.06% total vacation cost)
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2012 Expenditures Total : - $3224.33 USD - 22 days at $146.56 per day
Canada Dollars Disbursed : $2743.90 CAD ($2842.46 USD) - at $0.9653 USD exchange rate
Fuel purchases - $2196.27 USD (68.11%) - 435.2 US gallons at $5.046 per US gal
Canada Dollars Disbursed : $1802.59 CAD ($1869.12 USD) - at $0.9644 USD exchange rate
354.0 US gallons at $5.280 per US gal within Canada
Total miles - 5116.1 (at 11.75 miles per US gallon) .4292 US cents per mile
Non fuel expenditures - $1028.06 USD (31.88%)
Canada Dollars Disbursed : $941.31 CAD ($973.34 USD) at $0.9671 USD exchange rate
Combined restaurant and tips - $367.55 USD (35.75% non fuel) or (11.40% total vacation cost)
Restaurant - $296.84 USD (28.87% non fuel)
Tips - $70.69 USD (6.87% non fuel or 23.81% added to restaurant tab)
Grocery - $200.07 USD (19.46% non fuel) or (6.20% total vacation cost)
Camping - $159.34 USD (15.50% non fuel) or (4.94% total vacation cost)
Gaming - $81.69 USD (7.94% non fuel) or (2.53% total vacation cost)
Gifts or souvenirs - $61.05 USD (5.94% non fuel) or (1.89% total vacation cost)
Admission fees - $40.74 USD (3.96% non fuel) or (1.26% total vacation cost)
Attractions - $36.86 USD (3.58% non fuel) or (1.14% total vacation cost)
Beverages - $26.15 USD (2.54% non fuel) or (0.81% total vacation cost)
Equipment - $22.24 USD (2.16% non fuel) or (0.69% total vacation cost)
Showers - $19.96 USD (1.94% non fuel) or (0.62% total vacation cost)
Parking - $5.17 USD (0.50% non fuel) or (0.16% total vacation cost)
Laundry - $4.14 USD (0.40% non fuel) or (0.13% total vacation cost)
Internet usage - $3.10 USD (0.30% non fuel) or (0.10% total vacation cost)
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Can't find my 2011 trip expenses at the moment but it is on a different notebook from the 2011 log, however my memory serves the per day expense was around $153 USD.
What seemed to really help on lowering the per US gallon fuel cost for 2013 was I made the adjustments of buying Canadian Dollars online when the market was favorable to do so by increasing my Canadian Dollars reserve to match the exchange rate at $1.00 par, which in comparison hedged a $62.52 USD saving fuel cost for 2013 fuel purchased in Canada, or converted to a $0.19 CAD per US gallon less price.
After withdrawing that reserve at $1.000 par to use for 2013, I deposited more US funds at the same time and converted some of it into Canadian Dollars at the $1.0250 USD rate, and sold the remaining US funds as my new reserve now stands at the $1.0313 USD rate for 2014 vacation, as I might increase that reserve rate for more purchasing power now that the current cash buy rate has just topped the $1.0700 USD mark.