Thespian*: But what would be its average duration?
(for someone who plays for the first time and seeks to make all -or almost all- the sidequests) ;)
Well, I played it for the first time roughly 17 years ago. And it took me about a week or two I would guess (besides playing other stuff, school and all that). Oh, and no internet guides.
Nowadays, with doing EVERYTHING I need about 8 hours. Two events are appearing based on luck, so they stretch it out a bit. But at least 30% of that time are due to my OCD with RoA 1. Most in RoA is optional. I think you literally only NEED two dungeons, depending how lucky you are in obtaining the maps. (you don't need all nine). The rest is for fun and games.
I would guess, someone new to the game, but with experience in that genre needs 8 - 12 hours depending on how much he wants to explore. Make it another two hours familiarisation if you are new to such RPGs.
It should be very doable in the timeframe of that contest. The brothel in RoA is easy to reach if you are in a hurry. I included that, so people can see the changes made in RoA 2 and how much better it plays. (Never the less, they should be played in order)