The trick to using the Olympus Trip 35 is to simply not overthink the technical stuff. There is just no reason to. Let's take the zone focus aspect for example. When I first started using the Olympus Trip 35 I was a bit obsessed with making sure I twisted the focus ring to the right setting. I would compose a frame and think to myself, “now should this image be set to the icon of a single person or the icon of two people!?” The thing is, the Olympus Trip will give priority to exposures that have slower shutter speeds (again that 1/40th of a second) and smaller apertures that have a greater depth of field. More often than not if you are in the ballpark, depth of field will work in your favor and the image you get will look just fine. Maybe not insanely tack sharp, but honestly, why are we all so obsessed with that anyway? Composition and being in the moment should far outweigh the goal of ultimate sharpness in your images. So don't fret over the small stuff! Leave that for when you take your Rolleiflex out for a spin. Instead just enjoy the process of taking pictures.
I've seen a couple of sources on-line from people who have modified their Olympus Trip 35's to work fully manually. I really don't understand the purpose of this. The Olympus Trip 35 is a camera that gets some great results BECAUSE it is so simple to operate and yet made of nice quality materials with a better than average 40mm glass lens. If you want precise focus, perfect exposure calculations, and total manual control there are plenty of other options.
From a size perspective I find the Olympus Trip 35 to be just about perfect for those days when you are walking around town and just want a simple camera with you. It fits nicely into a coat pocket, a purse, or a shoulder bag without taking up any more room than your smart phone or a tin of breath mints. In your hands though it feels like a camera. Like an actual real honest to goodness camera. Despite its size it doesn't feel awkward or difficult. The few dials and controls that you need to use have a nice resistance and weight to them and aren't hard to find by touch. The viewfinder is better than one would expect from a camera of this size and I never have difficulty with framing or just popping the camera immediately up to my eye to shoot.
If there is one downside to the Olympus Trip 35 its the fact that this is not a great camera for low light situations. In fact, without a flash, it is pretty darn near useless in low-light. If your lighting situation is too dim for f/2.8 at 1/40th of a second with ISO 400 film then the camera just simply will not fire the shutter. Instead you will see a little red flag appear in your viewfinder indicating there is not enough light to properly expose your film. There are two solutions to this problem. First, you can always pop a cheap and tiny flash onto the camera's hot shoe. I have a tiny little Vivitar flash I bought at the thrift store for three bucks that works nicely. Or second, just move the aperture ring away from the “A” setting and over to f/2.8 and take the picture anyway. More than likely your image will be underexposed with the second option, but negative film often has enough exposure latitude that you may get a useable shot out of it. Ultimately however, the Olympus Trip 35 is really much better suited to outdoor and daylight work where there should be plenty of light and this is all a non-issue.