As a former triple user and someone who mainly rides in the mountains, let me suggest one other option. Get a compact crankset and replace the 34t ring with a 33t ring (available from TA Specialites). Pair that with an 11-28 rear cassette and you very nearly have the same low gearing and gear range as a triple.
Certainly, you can put MTB components on a road bike and get still lower gearing. The small ring on most road triples is 30t. Since this is a weight weenie forum, I was suggesting a way to get a very decent low gear for climbing (33tx28t) without weight penalty or the fiddliness of a triple. There is no reason for rudeness. And yes, I do know a little about bicycle mechanics.
Hi tantra, what you have written is 100% correct. Using an MTB 11-34 10spd cassette, compact 50/33 crankset, and a MTB M772/M972 SGS RD will give you low gearing of 33-34. Which is very low. Yes, a triple can run a smaller chainring then a 28T, as suggested even a 24T, which will allow one to use a closer ranged cassette, such as an 11-25, 11-28, or even an 11-32. A closer ranged cassette, like 11-25T, will provide closer cadence between RD changes.
A triple is usually heavier and we are talking road not off-road. A compact has a better Q and is a little easier to setup. Road RD's usually come in S or GS not SGS, where the GS form will allow an 11-32 and have a max total of usually 37T for Cassette and Crankset combination.
Eg. an 11-32 cassette = 21T, which will allow a max Crankset range of 16T. That is 21 + 16 = 37T.
You will need an SGS RD, which generally allow a max total of 43T to 45T, to extend the range of the crankset.
Eg. an 11-32 cassette = 21T, which will allow a max Crankset range of 22T to 24T. That is 21 + 22 = 43T or 21 + 24 = 45T.
Anyhow, both will work, and there are pro and cons for each arrangement.
As tantra mentioned the compact setup should be lighter and a little easier to setup and maintain.
This is why hi-end MTB's now run dual cranksets with an 11-36 cassette.