I would never rely on track connectors to conduct power the track, indoors or outdoors, but would bond each section to a power bus running round the track via droppers.
For the mains bus I'd by a drum of 2.5mm cable from your local DIY store or the internet. This is WAY over rated for the power used by a model railway. But we are not talking about power levels here, but losses due to the resistance of the cable. ALL cable has resistance the thicker it is less
less it has.
1.5mm wire has a loss of 29mVDC per meter per amp (rough figures for single core cable)
2.5mm wire has a loss of 18mVDC per meter per amp
So if you have a 30ft out and 30ft back track outside that is roughly 20 metres. 1 large 00 Loco can draw close two 2 amps under heavy load.
So using a 1.5mm Bus you would lose 0.029X2X20) 0r 1.16 volts
OR using 2.5 mm Bus you would lose 0.018X2X20) 0r 0.72 volts
Now this doesn't sound a lot but every soldered inline connection to the track WILL reduce the voltage further.
Just relying on track connectors each will introduce a resistance that with time will get worse, don't do it !!!
Try to keep the bus with as few joints as possible everyone can introduce higher resistance and possible faults.
I have seen a layout where every dropper was met with a joint on the bus line itself, not just attaching the dropper to the bus. it caused a huge total resistance and had to be rewired.