I would also suggest flex track. The flex allows much more freedom to make curves of varrious radii. More importantly, rail joiners should only be used for a mechanical connection to keep rails in alignment, electrical connections should always be soldered. You could solder drops to rail joiners and then solder the rail joiners to the track, but the pounding of trains through the joints especially on curves may crack the solder and creat electrical problems. I would suggest using buss wires of fairly heavy gauge wire under the layout. I like to use #12 Romex for the buss wires. It is heavier than needed, but it is cheap, may be free if you know an electrician who could pass on a few scraps; and it is easy to color code your positive and negative wires under the layout to avoid shorts. I solder a drop to every rail before I put the track down. If you accidently melt a tie or two, don't worry about it. I stain some wood ties to match the plastic ties in color, and cut out any melted ties. Then when I put the track down, I slide the wooden ties into gaps left by the removed melted plastic ties. After you add ballast to the track, the difference in the ties disappears. For your drops, you can use very fine wire, 22 gauge or even smaller, just make the drops short, no more than 6 inches long or so. Solder to the outside or bottom of the rail. If you solder to the outside of the rail, bend the drop wire tight underneath the rail and drop it through a small hole drilled in the road bed between the rails. Again when you add ballast, the drop wire will disappear. Solder a drop to every piece of rail, You may want to hold off on sodering drops to turnouts until after you have had practice on the flex track. On turnouts, you need to make sure that your drops don't interfere with turnout operation.
