Did exactly the same thing on one of my solo landaways as a student PPL. Luckily it wasn't a busy day, but there were a couple of others in the circuit. I don't think I got close to anyone. Fortunately I realised when at around 1500 ft and crossed over to the real deadside PDQ.
Now, if I'm landing away somewhere, I'll sketch out the r/w configuration on a piece of paper. Then I'll phone up the airfield to check they're open, which r/w is in use and which circuit direction. I'll use a coloured pen to draw in my rough route on the r/w diagram.
Then I check and double-check. And if someone else is in the clubhouse I'll get them to check again!
Bear in mind that I did all my PPL training from Coventry, where we join base leg. So my grand total of O/H joins could is fairly low.