Mike, no arranger involved. It's been a year, so I have to try to remember the process on this particular rough. Use anything laying around for the rough. It was an Alesis drum machine and a keyboard controller, with an old Yamaha tone generator. thwe piano was an old Yamaha Clavinova CPV 65. Organ was a Hammond XB-2 (ancient stuff). Used either a Yamaha 4-track or a small Tascam. Always lay down the drum track with the bassline first and multi-track 2nd. Entire process for a 5 minute piece (which is then louped, for a demo to the client) is a couple of hours. My son, who is the audio guy and IT guy for my company, in addition to being a passable bass player chooses the recording equipment, engineers and mixes and I just play. The final is done with all real instruments at a conventional studio owned by a long-time friend. I play keys, percussion, bass, guitar and hire a horn section, drums and sometimes a 2nd guitar player. The hard part of the final is writing and recording the piece in sections so it can be edited to time. Budgets allow us to go "top shelf" on the final.
Hope that helps.
Russ