towing travel trailer with full holding tanks?

Some cities' public works will have a dump station. I have one a couple of blocks away from me that charges $1. It wasn't even listed on dump station websites.. I found it on some forum somewhere when looking for a close place to dump.

The only issue is that it's Mon-Fri.. but luckily there is a state park within 5 mi from my house that allows you to dump for free.