"Route 31" is the "Mt Glorious", a FANTASTIC drive with spectacular scenery, but...
it's the local bike road. Most are pretty cool with the cars but keep an eye out for the squids on the rice-rockets overcooking it. Some of the corners can catch you out too, decreasing radius sort of stuff. If it's decent weather,as you climb the hill you'll see some cars parked on the north side of the road for no apparent reason. They're at the swimming holes at the bottom of the valley you're climbing, which are good fun. Very limited parking. Word of warning, at the weekend
lots of cops in unmarked cars hunting the bikers.
If you have a few days off consider Tangaloma (
Tangalooma Island Resort | Tangalooma Holidays | Moreton Island Tours & Photos | Moreton Bay Brisbane Tours | Family Holidays QLD | Day Cruises), also pretty cool.
Have fun in Brisbane. It's a pretty safe city. Take care in Fortitude Valley away from the crowds. The walk along the river is good, especially at this time of year, but I wouldn't do it after dark. Resturants? Ecco is pretty good, not cheap. Best in Brisbane is Montrachet at Paddington,
great food, less pretentious than most top-end resturants. Best coffee? Jett, 38 Chermside St, The Grange (Mon-Fri 6-2, S,S 8-12). Vanessa also makes the most fantastic slices, muffins, etc. Hassle to get to from the City though. The Sunday markets along the river are your typical Sunday markets, nothing special. Museum not really worth the effort. Botannical gardens good for a run. (again, care after dark).
Have fun.
BTW, if you're staying in the City have lunch at "Yi on Edward" (41 Edward St, 3211-8320). Vivian owns the place and she's great. Ask for "the meat pie" for lunch. House speciality, trust me, you won't regret it. (More than reasonable $$ wise). It's to a normal meat pie what a 959 is to a 924.