Justin
HOn30 and HOn3 are not commonly thought of as beginner scale/gauges. There is not a lot of RTR in either one.
The most common way that one gets started in narrow gauge is to add a small amount of narrow gauge track to a standard gauge layout. Then as the narrow gauge bug captures your soul, you start to focus more and more on the narrow gauge. Finally, you realize that you no longer have any interest in the "standard" world and rip up that excessively wide track to make room for more normal (as in narrow) track.
A lot of very fine, very small HOn30 layouts are featured on Carl Arendt's site,
http://www.carendt.com/.
If you are looking for table top-sized plans (door, 4x6, 4x8, etc), any HO or HOn3 plan can be successfully done in HOn30.
N scale layouts can often be adapted, particularly if the track is not crammed in. To adapt an N scale layout, don't pick a plan with 9" radius curves, those are likely going to cause problems. Use plans that feature bigger radius curves. Parallel track spacing will likely have to be widened a little, and vertical clearances also have to be increased. Structures will take more space than in N.
Just like any other scale/gauge, the track plan that suits you depends on your theme, region of country, prototype (if any), era, and operating preferences. I have not seen or heard of many large HOn30 layouts because of the time required to build and kitbash locomotives and rolling stock. Frary's C&DR is the best example of a good-sized HOn30 layout I know of.
Hope this helps you walk the narrow way....