I'm sure someone in the industry will give a better insight, but in the meantime my assumption would be that you'd work at a similar pace to the time estimates in the freelancing section of the wiki. http://wiki.polycount.com/wiki/Freelance I don't think it mentions environments though.
As okidoki mentioned above, we have a wiki with tons of curated resources. We even have example character meshes! http://wiki.polycount.com/wiki/BaseMesh And tons of example wireframes to examine and learn from http://wiki.polycount.com/wiki/BodyTopology http://wiki.polycount.com/wiki/Limb_Topology
Here's a walkthrough of one artist's process. http://wiki.polycount.com/wiki/Roguedevelopmentdiary More stuff here http://wiki.polycount.com/wiki/Character
Awesome tips people! Added a new wiki section for this. http://wiki.polycount.com/CategoryGameIndustry#Freelancing I can't recommend this book enough. Graphic Artists Guild Handbook: Pricing & Ethical Guidelines