Restroom trailer leveling: how much slope is too much for the steps to be safe?

Any slope under the steps is too much for safety. The steps must rest on level ground to prevent tipping or tripping. A 2 or 3 degree slope might not sound like much, but it can make the steps unstable, especially for guests in heels or after drinks. Move the trailer to a completely level spot where the steps can be placed on firm, flat ground. If moving isn't an option, build a temporary platform with pressure-treated lumber or rental staging to create a level surface for the steps. The platform should be wide enough for the entire step area and secured to prevent shifting. Your service access is fine, but guest safety comes first here. I've seen a near-miss with a slightly sloped step at a reception, and it's not worth the risk.