Looking for RV Parks in Madison WI area - Open Early

[MythX]

Hi everyone. We're needing to take a sudden trip to the Madison WI area and need to find a park. They're nearly all closed for the season still, not seeming to open until May. I'm hoping someone can point me to a place that's open. Even if I find one that can't supply water, I can probably work around that. A couple limitations I have, is I must be able to work from the location, either WiFi, or decent cell service, and my 5th Wheel is 43 feet long.

Any suggestions?

Thanks