I was recently at a campground and noticed when I removed the cover of the park's drain, there were a lot of drain flies AKA moth flies. I suspect these would then go up the hose and take up residence in your tank. I had this happen in our house and had some difficulty finding a way to get rid of them. Finally by using a foaming drain cleaner (one that starts out as two parts and combines as poured), they were gone.

I agree. I am afraid that I don't see a problem. I regularly drive around with a partially filled black tank for weeks on end. 

Am I missing something??

BUT, our situation is a little different from what you describe.  Our tank has never been anywhere near full, always less than 5 gallons; and, it contains no solid waste, no paper or #2.

With my first boat, I had a porta-potty that I regularly dumped in a toilet, but it only held about 4 gallons and had handles and a smaller dump port so it was easier to deal with than a plain old bucket; still an unpleasant experience, though.

Personally, if the tank was contained more than about 4 gallons of waste, contained paper, or had solid waste in it, I would make the effort to drive to a dump station and pay the fee.  Fortunately for us, we live near a Maverick gas station that offers free dumping.  If i was in need of urgent dumping, I'd go there, buy some gas and dump away.

If you are using a biological tank treatment like TankTech's Rx, Unique Products' Digest-It or other similar treatment, just let it be until you go out again. It won't hurt a thing. In fact, that is what TankTech's recommends.

Otherwise, are you on a septic tank or on city sewer? If on city sewer and you have access to a 3" drain (may be a pipe sticking up with a white screw-in cap), you could just get sufficient drain hose to reach and dump there. I have two drain fittings in my yard. One is near the foundation and the other is out near the property line. I verified that it is the drain by flushing the toilet inside and observing to see if the water flow reflected that flush. Once I was sure it was indeed a sewage pipe and not a storm drain, I went ahead and just use that instead of searching out a dump station. After all, I am already paying for water and sewage every month.