Check out this article detailing some G-Scale (Garden) track plans I’ve discovered on the web: Model Train Resource: G-Scale (Garden) Track Plans To Inspire Your Own Layout Designs Thanks. Aurelio
Those track plans have a distinct lack of imagination i.e. they look like the stuff that was published 40 and 50 years ago for the smaller scales. As always strictly my opinion and yes, I'm building a railway in the garden
Alas, G-scale does seem to suffer from a certain simplicity outdoors. I think it's because of having to share space with kids, pets and garden activities. It's good that you have the space though, because some of us dont' even have that. Be sure and post pics here when you're finished.
I'm sure there are plenty of folks, like me, that do NOT have h space available to build a decent garden railroad. I'm trying to shoehorn my layout into the minimal space I've been given!! Would love to to large, especially in curves. Started with 8 foot Diameter curves. Lucky to just fit 10 foot Diameter curves in the front. Although, more space means more trains. More trains means more track. More track means more money! And time and....... However, a smaller railroad also mean less work, maintenance etc.. I'm just happy my folks allowed me to build what I have so far, and are letting me build what I want, almost anywhere I want!! And I'm already working on simplifying what my original plans were. Just MY personal opinion based on personal experience.
More space doesn't need to mean more trains, to me it means more room for landscaping, structures and all that other good stuff. Twenty years ago when I was teaching "Model Railroading - the Basics" at one of the school boards I tried to impress on people (from 15 to 70) that there is a lot more nature out there than railway. On the curve dilemma, it all depends where depending on the "lay of the land" railroads generally follow the contours. In and out along hillsides, up and down and sideways on the flat sections.
I built a small outdoor railroad 20 years ago this February. One spot is a tad "busy", the rest stretches out over a good run, down along the back fence, around the "shed" to the lower level. I started with 6'8" radius, that's my main line minimum radius...works for NG steam. I have never been one for "trackplans", rather eyeball and engineer to the landscape.