I’m actually in a really good place to answer this because ALL of the Madison episodes are, technically, crossovers. Where Madison appears in other shows. It’s a little easier for me as I can take liberties with the OTR series I wouldn’t do for modern audio drama podcasts, but the principle is the same.
I am a trained television sitcom writer. And I have written scores of spec scripts. A spec script is a “speculative” script you write of an already established television show to showcase your writing skills. Agents use spec scripts basically as your portfolio to be read by show runners to book you work. You are tasked with creating a new story for the series, but you absolutely must capture the tone, voices and formatting for that show to where anyone reading it would 100% believe this script was actually from that show.
My technique for capturing this is IMMERSION. For all of the OTR series I adapt, I throw myself into the series. I listen to the show daily, episode after episode, to where I can hear the characters in my head. I learn the tone, I get a feel for how the stories are presented. I want to be able to alter the show while still remaining true to it. And that’s how I treat my crossovers with other audio dramas. I listened to every episode they’d put out. And I only listened to that show while I worked on the crossover (I didn’t want to muddle my mind with another show). I wanted to hear that character’s voice saying my words.
Then, of course, I hand the script over to the other show’s creator. I don’t get to do that with OTR, so it’s a nice bonus when I write these crossovers! That creator gives me notes and I tweak the changes before we go to the recording draft.
It is a tricky bird making sure you are servicing the other audio drama. You need to know going in how much control you are looking to share. Because you should still keep true to your own brand and tone for your series. Additionally, you should add extra production time to the episode. Going back and forth with another creator adds time. Most of us are doing this on the side while balancing other life-stuff. So plan ahead to make sure you don’t find yourself running out of time for post production. I am a huge believer in a consistent release schedule. So make sure you have enough padding to meet your deadlines.