I would ask what kind of paint at that price. I shoot Dupont Centari, acrylic enamel. Very durable and polishes out like glass. A quart of paint, hardener and reducer will run almost half of your quoted cost. And are they going to include a wet-sand and polish for that price? To get a professional high-gloss finish this last step is required and adds to the labor time.
The gas tank removal is a bit of a chore, but nothing extreme. The pump is on the bottom of the tank with a quick connect fitting, press the tang and it pops off, fuel flow stops. And there's a quick connect for the power lead for the pump. Same thing, press the tang and remove the lead. There is a vent hose and an overflow hose on the left front area under the tank, has the cheapy spring type clamps, can be re-used as there is no high pressure or anything on them.
Remove the hold-down fasteners and you can lift the tank enough to remove all the plumbing, then lift the tank off.
The cap assembly ring is unbolted and that includes the cap itself, set aside and dump out any remaining fuel. The tank color goes under the cap assembly so you need to mask off the opening and plug the overflow vent. That way when you open the fill cap you don't have the old color showing.
The other parts are very easy to remove, just press-pin fasteners and a few 6mm bolts. Clean prep the inside faces of your fairings, front and under the seat, and have them sprayed too. Otherwise you'll see the old color inside the front fairings and under then seat. This may add some cost as you have to shoot both sides, but well worth it for a professional look.
Mine was green, wanted black, so I did mine in my garage at 120 miles.
EDIT: if you use color rite or house of color they are decent acrylic enamels that use a proprietary reducer. They should still be polished on completion. A cross-liner harder makes enamels fuel proof and improves durability.