Here's the way I think about this issue. It's all based on glycogen depletion in the muscle and in the liver (in the case of long workouts). For optimal muscle recovery you have to replace the glycogen as soon as possible.

The body uses energy from different sources (glycogen in muscle, glycogen in the liver and energy derived from fat metabolism) based on several factors. All of these sources are being utilized at any one time but in differing proportions. How each individual utilizes energy is affected by many factors, length of time exercising, intensity and the body efficiency at using certain energy sources.

All of the above I know is pretty accurate, although simplified.

Now I'm branching into a my understanding of what this means practically. This is my interpretation and realize that nutrition is certainly not my expertise.

Any activity of high intensity of more than what could be considered a brief bout of exercise, should be followed by some replacement, how much will depend on the length of time, but I would guess that anything more that 30 min at intensity would constitute enough activity to warrant a full 200 cals ASAP. High intensity depletes muscle glycogen first and quickly.

In an unconditioned individual you will see a lot of glycogen used even for lower intensity aerobic activity so you would again replenish certainly for anything more than 30 minutes. Unconditioned individuals do not have the ability to metabolize and use other energy sources as efficiently so they will preferentially use muscle glycogen.

In a more highly conditioned athlete, it will take a lot longer to deplete muscle glycogen at lower levels of intensity, so that is probably something that a person would need to experiment with. Having said that, even if you're not depleting your glycogen too much on a 2 hour ride because it's low intensity and you're taking in carbohydrate while you workout, you're still burning enough calories to easily make up for a 200 cal hit after the workout and you're body will just use it where it's needed - in the muscle, to replace liver glycogen or just as general fuel. So why not go ahead and have that glass of chocolate milk?

A conditioned athlete, exercising at low intensity for less than 1 hour is not likely to deplete their muscle glycogen substanially, so I wouldn't worry about replenishing that much.

As for climbing versus riding, I think that has to do with intensity. I consider climbing an intense effort workout, similar to weight lifting. So I would definitely stock up after a session.

Beer does count as quick carbs and I often use it for recovery . Unfortunately, the alcohol supresses testosterone and will decrease the amount of stimulation you're body will get for new muscle growth and it doesn't have the protein and fat that you want. Zen is right, chocolate milk is the best and cheaper choice.

There's my .02.