I can't help with a painter as I'm in VIC, but in my case, I did all the "dumb"work to help save a few bucks.
Mine is a total resto so motor and subframes are out. Don't know what your engine bay looks like but if it's a bit ratty, it might be worthwhile pulling the motor out and cleaning it up as well as get the engine bay painted.
Body wise, I stripped it all back to bare metal. Originally with an orbital sander but be very careful to not get the metal hot or it will buckle a bit and add heaps to the repair bill. I found that too slow so resorted to paint strippers. Took the lot off and then sanded out any old bog that was in it.
Wire brush on the end of a drill all the rusty areas and then rust treated them. Finished up etch priming everything to stop surface rust on the bare metal. I went overboard and did inside the boot, inside and outside doors, bonnet etc as well as stone guarding the lower parts of the engine bay and sills. I also cut off the seam covers as they had a bit of slight rust under them that needed attention.
Cost wise, all the materials for the body prep cost a bit over $1000 (sanding stuff, numerous cans of etch and primer, strippers etc) and that also included painting all the suspension components etc as well as all of the inside including the floor. I didn't keep a track of how many hours I spent doing this but it was quite a few. I figured all this stuff was just elbow grease type work and my hourly rate is way less than a panel beater.
As long as you etch prime the bare metal not long after you strip it, damp weather shouldn't be a problem. My spray painter buffed all my etch off anyway and 2 packed etch and primed it after he did some body repairs. I'm sure you'll find some hidden bits under the paint that will need attention.
I also took everything off the car including doors, boot lid, bonnet, all the brightwork, lights etc and repaired the door hinges. I stripped all of these things back to bare metal and then etched and primed ready for paint. When you start pulling all of this off, you'll no doubt find rusted nuts etc that all take time to remove. Cheaper to do that yourself I reckon.
If you go down the path of pulling everything apart, take lots of pics and write stuff down. Draw pictures and take notes to help you remember how it all goes back together. Label all the wiring so you know what goes where.
I've really enjoyed doing all this, as well as all the mechanical stuff that I can. This forum has been terrific and there's always a bunch of blokes who know what to do and ready to help. I think there's a degree of pride in doing things yourself rather than just paying someone else to do it all.
Paint wise I'm going to use 2 pack as I'm sure nearly everyone uses now.
Cost wise, I'm not real sure. My painter is a local bloke I've known for years and who won't rip me off. I didn't bother with a quote as it's hard to know exactly what's required until it's stripped back. I'm guessing somewhere between $3 - $4,000 given there was quite a bit of repair work required. However, if you don't know and trust your workshop, then a quote for the actual spray job would be necessary before you start. Maybe try and get a price for the paint job assuming you bring in the car in etch with no repairs required. Then perhaps an indicative price per hour of labour for repairs.
Personally, I find the smaller, owner operator panel shops a bit better to deal with. The big flashy ones tend to be real expensive or only want to panel replace modern cars. One joint I rang wanted $20,000 just to paint a fully prepared shell. Another quoted $10,000.
Hope it all goes well whatever you choose.
Cheers, Rocky