Actually your cost per mile is more like $4 since you would depreciate an asset over three years for 50% of its value, depending on your business and applicable tax laws. Of course if in the next 5 years you total 11200 miles, then it cost you $1/mile.
Your calculation is correct if you sold your sled for $0, meaning it was 100% depreciated and worth no resale value.
Well, it's not a business, so no tax writeoff, so $4 is not a good estimate. But you would probably not use the full $11,400 in the calculation, since the sled has a residual value after service life, as in, "how long do you plan to keep it"?
In this case, to calculate actual cost per mile for one year, figure current value if sled is sold on open market today, subtract that value from cost basis, (1 yr. depreciation) and divide by your 485 miles. This is the true cost to ride for this year alone. Not including gas, oil and lodging of course. In a business, these costs are not considered part of an assets capitalized value, so you wouldn't include them in the basis, but for total cost per mile - why not make yourself feel max pain?
Yes - I happen to account for fixed assets at a corp., just one of my many acctg. functions.