The scheme
I've more-or-less finished my proposed track plan, which you can see below. You can also download a PDF version for a closer look.
The plan models the key stations from Kamakura up to just before Enoshima, with one or two minor stations as well. It's obviously a huge compromise to fit everything into the available space, but I think it ought to work. Some of the curves are pretty tight, but it is more-or-less a tram layout so I don't forsee any problems there.
Outline
The line folds back along itself to give more running length, and the gradient falls from Kamakura towards Enoshima in order to allow the loop track to run back underneath Kamakura station. The height difference between foreground and background also helps to make it clear that the scenes are separate rather than connected. I've seen this work well on other peoples' layouts so hopefully disbelief will be suspended here as well. The stations are also staggered so that a station in the foreground mean plain track in the background, and vice versa. The exception is the passing loop, but this will be quite narrow since it doesn't have any platforms or other station parephenalia, so hopefully will not look too busy.
The pointwork is all based on the real thing, with minor changes to save space where desirable, such as the loss of the outer passing loops in the JR station and using two shed roads rather than four at Gokurakuji. The only significant exception is the point and tunnel at the left hand end, which don't exist in real life but are needed here to give a continuous run. If you were going to do this as a true end-to-end this could be left out, but then the left end of the route would be a bit sorry-looking without Enoshima station.
Tricky things
The right-hand side of the plan was quite straightforward to work out and follows the prototype quite closely. I've sacrificed two of the shed roads at Gokurakuji to make things fit - the width is there, but the pointwork ladder for more roads would take up too much length. If you used smaller radius points it might be possible to squeeze another one in, but I wanted to be able to use the Peco Code 55 track.
The left-hand side was more difficult. In the foreground, I had to decide between Kamakura High School (Kamakurakoukoumae) station, which is right on the sea wall and crops up frequently in tourist photographs, and Koshigoe station which fits into a tiny triangle between the railway and road right at the start of the street trackage leading up to Enoshima. In the end the high-school looked like a better bet, since it's more likely to be familiar to people.
The background wasn't entirely straightforward either. Having purchased Kato's lovely Narita Airport Express set, which runs from Narita Airport almost (but not quite) to Kamakura, I wanted to make space for the JR station at Kamakura next to the Enoden terminus. Given that the model Narita Express is six coaches, this was quite tricky, but I think it just about fits. The JR line disappears quickly behind the backdrop, and at the moment is limited to shuttling a single train in and out of the station. It's vaguely amusing that on a typical mainline layout it would be the tramway which will shuttle back and forth in the background, but here it's the other way around.
Operational possiblities
Apart from the obvious watching the trains go round, operation is likely to be pretty prototypical. Services will run from Kamakura, all the way around the layout and back to wait underneath Kamakura station. After that, they reverse their journey and go all the way back. Hase and the seafront loop provided opportunities for passing so things could get quite busy if all the single-track sections are occupied.
The depot provides a place to store spare rolling stock (useful since Modemo keep bringing out new variants and different advertising liveries - must collect them all...) The sidings are all long enough to make up two-unit trains from single units and break them down again, although manual intervention may be required since the provided inter-unit couplings are neither automatic nor self-centering. Possibly alternative couplers could be substituted.
The JR station only has enough track to shuttle a train back and forth - this could be automated. It does add the potential for Enoden trains to make or miss connections at Kamakura though.
I suspect DCC would be quite appropriate for this layout, but I haven't really thought about the electrical side too much. At the moment I'm using a spare Märklin Z controller to run things on the test track, which gives excellent performance and reasonable top speeds. There is probably room in the tram bodies to install DCC decoders though.
Ways to do it differently
The real Enoden runs many services with two units coupled together, although some of the the traffic is single units (i.e. two coach bodies articulated over 3 bogies). I wanted to allow the longer trains to add some operational interest, which means all the platforms and passing loops have to be just over a foot long. You could save a lot of space limiting traffic to single units, although I was concerned the short platforms and passing loops might look a little odd.
You could also keep Koshigoe by losing the passing loop and moving Kamakura High School station onto the middle board to make room. I thought this would be slightly limiting since you then have a very long section of single track, so opted not to go that way.
More variety could be added to the JR Yokosuka line shuttle by having two tracks behind the backscene instead of one. I thought that on 500mm wide boards this was too much of a sacrifice - it'd work, but it means losing out on some depth somewhere in the modelled scene. If you had wider boards this wouldn't be such a big deal.
There is a possibility for future extension at the left-hand side, where the street trackage could continue to Enoshima Station, and then on through the suburbs to the elevated section and the terminus at Fujisawa. I would think that to do this justice, and to fit on a bit more of the JR Yokosuka line in order to run trains on it properly, another two 500mm x 1200mm boards would be required, such that the entire layout would form an elongated L, or perhaps a lopsided U shape.
Adding Enoshima would increase the scope of operations and provide more tram storage since the station has a small fan of storage sidings. I wonder if there's enough space in the dining room?