I forgot to mention pneumatics for points, really low maintenance all of my line points (switches) have been powered by Air since I started using it back in around 2000. I have used Del Air, Easy Air (both now unavailable) and even have some Sunset Valley on my line though I find the Levers a little in the small size they do make a nice neat panel. All of my Lines go through modest sized Electrical Trunking, I spray it Grey to match in better on the line some I have even scored with a saw to look like Railway Cable Trunking runs. This for you will have the same benefits for me, easy access for revisions and perhaps some protection against critters. I have had ants nests in the trunking with no ill effects. The trunking is also useful for Electric Cable runs as I used to run DCC, but in your case with battery any such runs may just be for Building Lighting.
As for those water courses, embrace them use large rocks where they go to make like a River and run bridges over for the Track. I have made fake water courses on my line using Cement Based on top of Butyl Liner with the rocks bedded into the cement, so long as you preserve the natural route and depth of the water this should work well for you.
Welcome to the forum cvcanada. Having gone through the electrically driven - manual - air powered cycle of operating my points/switches, I can thoroughly recommend using a pneumatic system for these. I too use the readily available SVRR system, as it is now distributed in the UK ( the guy who makes it is a Brit' expat' !). The SVRR system is based on modified standard mainstream Clippard pneumatic components. It's ideal if you live in areas where climate extremes, water (precipitation) and heat, may affect the reliability of electrically driven systems and require excessive maintenance as a result. I have adapted their turnout motors to operate my semaphore signals. I power mine from a small airbrush compressor with a 3 ltr reservoir tank.
Looks like you have a major project on the go there. What do you plan to run ? Max