It's hard to tell what they'll charge and how many points you will get for a fixed week. It will depend on what you have - location, unit size, season and the resort.
Trading within the system is good if you can plan ahead. If you can book 11 months out you are likely to get your request although a few resorts (maybe 2 or 3, Sanibel and Tradewinds in Florida and Wilderness Club near Branson, MO)are nearly impossible to book even 11 months out.
Bonus time are hard to get during peak periods of the resort location but they are available. I think it is $59 per night for a studio, $69 for one bedroom and $79 for two bedroom, etc.
In addition to this forum you may want to check out some of the Bluegreen Facebook pages like Bluegreen Timeshare Secrets for more information about BG.