My Rollei 35S has been dragged up and down mountains and around towns for years. The meter is on top, so when looking at the top of the camera everything is visible -- meter, shutter-speed dial, aperture, distance. Very quick and simple to use. Estimating distance is easy enough, and you can always carry a piece of string for 3ft /1m if you really want to. Also, the shutter is designed to be cocked 'all the time', when carried with the lens collapsed, so that isn't a problem and that also blocks the shutter release to eliminate pocket shots. The original wrist-strap is a strong and excellent design, so find one of those too.
The meter has no off switch and relies on the high resistance of the cell in darkness to actually be 'off', which is another reason why a small belt-case is a good idea. The battery is most conveniently a silver cell in an adapter, no camera adjustment required and which then lasts for ages. Very, very practical cameras.
So, in other words...
- You can't see the shutter speed and aperture, unlike the Olympus 35RC and other cameras. You need to take your eyes out of the viewfinder.
- You need to keep it in the dark to prolong battery life. By the way, you can't change the battery on the classic R35s without first removing the film, so it's a good idea to keep the camera on a storage case. Even better, to protect the lens, unlike the Kodak Retina, Minox, and Olympus XA, all which feature integral lens protection.
- So you keep it in the "dark" case. Now when you want to take an impromptu shot you need to do four steps:
1. Take the camera out of the case.
2. Push the button, twist the lens, pull it out, twist again to secure
3. Set focus distance
4. Place your eyes in the viewfinder and shoot.
Still very slow for a travel camera...
The compact SLR recommendation is a good one.