Hi Paul
Just thinking about good spots....you could probably try Tinaroo, up at the camping grounds, or one of the local footy fields. Whereabouts are you in Cairns?? That'll give me a better idea of where you can setup. The Tablelands would be good, but that means at least a 30 minute drive or so. Actually, it'll get you out of most of the light pollution, which is good. Plus at this time of the year, it's a lot drier than in Cairns and the air up there is a lot crisper and still. However, there should be plenty of spots around town to setup in.
Now, for your scope. If you're going to be moving around, you want something reasonably portable. You could pickup an 8" reflector on a HEQ5 mount for that much ($2000), but it's not exactly portable, in so far as the length of the scope's tube and weight of the rig. With a camera attached, you'd squeeze in under the mount's carrying capacity, so you could get away with the lighter mount (instead of having to go for an EQ6, which is also more expensive). If you goto
Bintel, you can pick up a HEQ5 mount and Sky Watcher BD200 scope for $1950, or you could goto
Andrews Communications and get similar (except scope isn't quite as good) for $1800. You could go down a size to a 6" on the same mount and pick one up for $1500-$1600 or less. If you're willing to forgo GOTO, you can pick them up for substantially less. At Andrews, an 8" on an EQ5 mount can be had for $800-$1000. But if you want to do piccies, you do need a steady mount. More so than anything else. You could even pickup a 127mm MAK OTA and the HEQ5 mount for under $2K (or on an EQ5 mount for $1750 at Bintel) or an ED80 refractor and mount for $1900 (at Andrews). An ED100 pushes your budget over by $200. There's also a special at Andrews on the gold tube 150mm MAK Pro's on a HEQ5 mount for $1999.
Thing is, apart from the scope and mount, you also have to buy whatever bits and pieces you want for the scope and you need to budget for them as well. So it's a trade off, really. Unless you buy some of them at a later date and go for the scope/mount first up. Another thing to think of is tracking. Yes, you can take piccies of the planets and the moon from a dob, but if you want to snap star clusters and such, you need to have a mount that can track. Not necessarily a goto mount, but one that can follow the movement of the objects through the sky. A goto mount is a bonus, especially for noobs as it helps them to find the objects and it's convenient (for us that are experienced...also for noobs). But it's not essential to be able to take piccies or for visual.
Hope that's been of help