I was brought up in Hull, and as a young lad, myself and a few mates used to cycle to Paull and I vaguely remember exploring the ruins of an old fort. Would this have been what is now a museum?
More recently, while visiting family at Christmas time about 3 or 4 years ago, I decided I needed to get out for a short walk to clear my head (as is usually needed at that time of year). I got in my car and somehow got drawn to Paull, parked up and went for a stroll. I'm pretty sure I followed a similar route to yours.