Having been stuck in the mud 4 times, in the past 2 winters, this is what i did.....First time, dug out behind the tires and laid cement stepping stones down to drive over. (A Florida RV park guide, in a golf cart, did a nice job of directing me right into the situation) Second time, laid 2x8 strips of plywood down. (courtesy of a Florida RV park) Third time, shut the coach down, went and had a drink and dinner and addressed it the next day, when it wasn't raining, and put some rocks and gravel behind the tires. Fourth time, dug out both ahead and behind the tire and laid down 1/4-1/2 gravel. (at home in Oregon in a December rain I was trying to go up a slight grade so I had to roll the coach back onto the gravel to roll forward)
Don't try to "rock the coach". Also, the more you sink the tires, the more work it is. Stop as soon as they start to spin and get started with something solid to roll up or back on. And last thing, when you get rolling, keep rolling, don't stop and don't go to fast.