The cities you mentioned are real cities with decent eating options (none except Fairbanks will have international chains, but that's ok). Depending on where you're going between them, though, the extent of the food options may consist of a picnic table where you can eat your own PB&J sandwich.
You might consider ordering a Milepost guide (reasonably priced on Amazon) and following the course of your trip and seeing just where the eating options lie relative to where you'll be staying. I'm having a hard time picturing where you'll be in between Skagway, Whitehorse, Dawson, and Fairbanks—there just isn't a lot of places you'd stop to see things in between those towns, so I'm finding it hard to think of where you'll be eating (with or without a meal plan).