Wow - that doesn't sound like much on-snow time, but a lot of people do it. I haven't, personally, because I live where I can ski every day. However, we have a 50k 5 miles from my house, and get a lot of people from Illinois, southern Wisconsin & Minnesota, etc. It can be done. As long as 2x per week isn't all the training you're doing. I assume you plan to run or something the rest of the time? Maybe run with poles? Roller ski?
IMO, if you have a plan and stick to it, and gradually work your on-snow time and distance up, you'll be fine. Not as fine as if you could ski more, but fine. If 2 days a week were all the training of any kind you could do, then I'd be skeptical.
You have until March. Maybe 4 or 5 weeks before your race you could consider getting in a full 50k. And remember, March snow is typically the fastest, easiest skiing! Unless, of course, it's too warm & sunny out - then it can be sucky-slow and miserable. Or, around here, the third option is a blizzard and -5F (been there, done that).
Your fueling plan sounds good - whether you're running or skiing doesn't really make much difference there. Just harder to drink with gloves and poles.
The Warrior Princess: 2008 Jamis Xenith Pro / Bontrager Affinity 1 (men's)
2006 Trek Fuel EX 9 / Bontrager Race Luxe
2007 Trek 520 / Serfas Terazzo
Amelia Pond (She travels long distances, has great adventures, and she's a redhead): 2007 Trek Pilot 5.0 / Bontrager Affinity 2 (men's)