James's excellent NRA RCO write up prompted me to give a broad outline of my one day regional version.
Apparently regional NRA RCO courses can be conducted over a single day and it was one of these courses that I opted to take. Obviously sitting the course, verbal, practical and written assessments makes for a very busy day but it is doable.
My RCO course started badly, my RCO Blue book still had not shown up a week before the course and finding copies in the public domain is rather problematical (Luckily I had some assistance in this area) A couple of calls to Maureen at the NRA saw the blue book arrive at the start of the week. I have obviously listened attentively to RCO briefs on numerous occasions but had no understanding of the nuts and bolts theory behind the role so I was staggered to discover exactly what is covered. The good news is a lot of it is common sense and quite logical, possibly the only area that can confuse is angles are given in mils.
I was well aware that I had to read, inwardly digest and totally understand the book prior to the course so having read the book cover to cover I started again with a highlighter pen to show what I considered to be significant points, I also wrote my own quick notes in the back of the book so if all else failed I could quickly refer to them.
By the Thursday I was at the stage where Christel was asking me questions based on the book and I was answering and explaining my replies, I find discussing something gives a better understanding. I also read the book in bed and when I found something I did not know I would read it to her and then expand upon it. Such an approach works for me and also stops her snoring (OK not really!) By Friday I was feeling vaguely comfortable about the whole thing.
Saturday saw me making a long rainy drive way out in the boonies to the class room for an early start. I was one of five people taking the course, two of which have since joined the forum :)
After a quick coffee and biscuits we went straight into the course which is based on a computer presentation which acts as the catalyst for further explanation and discussion so we effectively talked our way through the book, this for me worked very well as any potentially grey (To us!) areas could be discussed on further detail. We then had a brief break where we would prepare our range briefs. My RCO had already told me this would happen so I had mine written and had even used the Viking to test it and amend it accordingly. I had one additional line added as a consequence of the course so I volunteered to give mine immediately. With that part done and passed I could grab a coffee before going back to more reading. Next up was the practical section. I was mentally prepared for mine but was chosen to go last as I had started the previous part. Great but listening to the others was starting to confuse me so I made some notes on my phone to use as a crib sheet. Second bit passed.
Back to the classroom pausing only for a nervous trip to the block and final revision/discussion before the exam.
From memory the allowed time is 60 minutes, and the exam is a multiple choice/guess format. 10 questions are critical so drop one and you fail. The best thing with any exam is read all the questions first, with multi-guess I answer the ones I 100% know followed by the ones I think I know followed by the wild guesses. This exam was in open book format (you can use any revision/written material available) so really no reason to bomb out, however some of the questions are quite ambiguous and open to interpretation and it is a case of taking the best option available.
Once completed the papers were checked and scored and we discussed the paper in depth. I think I dropped two questions and one I strongly disagreed with the correct answer and it was good to be able to discuss it.
Day finished at 18:30 ish and I drove home as an RCO.
Roll on HME

My view is one day is doable however it is a hectic day and you need to be very well prepared prior to attending. It also requires a lot of concentration on the day, failure for me was not an option and I was pleased to have passed even if I was shattered by the time I got home. All five of us passed which apparently was unusual but good for all involved. I am RCO at a shoot on the 16th of this month which will be my first.