Beaches
This thread is ancient already, but I only recently found supercub.org and have been reading and reading and reading. Great site.
I think I've made most of the mistakes that can be made on the beaches of SE Ak, so let me put in my two cents, even though tardy. I'll go topic by topic, hopefully to assist those new to beaches. Everything is stated for tailwheel gear.
The nose of the plane will ALWAYS tend uphill, as stated elsewhere, because the CG is behind the mains. This will be most pronounced at low speeds, when the rudder authority and lift are minimal.
However, due to the slope of the beach, the entire airplane will tend to skitter sideways downhill, toward the water. This will be most pronounced at higer speeds, when there is sufficient lift to reduce the tires' side-loading capability, such as at liftoff. Leveling the wings will reduce the tendency, but not eliminate it. The reason is that regardless of the directon of the lift vector, as long as there is any weight on the tire(s), that reaction vector will have a component toward the water. With the wings parallel to the beach slope, the sideways skittering on takeoff will be pronounced as flying speed is approached, and the nose of the airplane must be pointed uphill with rudder to compensate. At the instant of takeoff the plane will then be cross-controlled, like a crosswind takeoff, so a little extra speed is desirable, and coordinated flight must be promptly attained. I agree that starting up high on the beach is good, however the skittering tendency must be anticipated and compensated for. If the wings are not leveled prior to liftoff, they must be leveled immediately upon liftoff, or the water will get uncomfortably close. On a very steep beach, it may not be reasonable to completely level the wings on the takeoff roll, in order to allow clearance for the uphill wing.
Crosswinds. In Southeast, there are usually tall trees along the shoreline, and a wind blowing from the shore toward the water is double trouble. It will not only make downdraft, but slipping into the wind may be impossible while maintaining uphill wingtip clearance. My story is to find another beach.
Direction of turns. Always turn uphill while taxiing. If the beach is at all steep, even more always! Turning downhill raises the tailwheel, and moves the CG forward with respect to the mains. That makes it all that much easier to dig clams with the prop. Expensive clams. My technique is to turn with a little bit of speed, quite a bit of power, and lift the tail just enough to get some of the weight off of it. That combination gives some elevator authority in case the inside wheel starts to dig. Use minimal braking to help the turn but also to keep the main on the inside of the turn rolling - so it won't dig into the sand as easily. If the plane doesn't want to turn completely, I get out and pull the tail around rather than turn downhill. Of course a very shallow beach angle can change that some, but I still vote for uphill turns.
I agree with testing for softness with one wheel - if it bogs down, pulling the wings parallel to the beach slope will pull the wheel off. I do it pretty fast the first time, say around 45 or so, note how it feels, and also go back around and look at how deep the track is. Then if in doubt, do it again, close to landing speed, ready to go around. Watch for variations in softness due to subsurface water drainage and buried seaweed.
Ok, there's my song re the basics. Sorry if it's redundant.