To resurface the floor properly meant removing all the internal furniture & fittings.
The more we stripped it, the more we realised that it was the right decision.
This trailer hadn't seen any maintenance in a long, long time, as was evidenced by the wasps nest in the heater intake (see below). There was many decades of crud behind & under every appliance, and in every cavity, which meant face masks and rubber gloves were in order.
This is what happens if you don't regularly flush your water systems
There was an inch or so of mud (not just dirty water) sitting in the bottom of the fresh water tank
The light cream color fluid came from the hot water heating tank
.... and they both stunk to high heaven!